Multi-layer composites formed from compositions having improved adhesion, coating compositions, and methods related thereto

ABSTRACT

The present invention provides an improved multi-layer composite of two or more polymeric layers at least one of which is formed from a thermosetting composition. The composite includes at least a first polymeric layer formed on a substrate and a second polymeric layer over the first polymeric layer, wherein in the absence of a boron-containing compound, the first and second polymeric layers have poor interlayer adhesion. The improvement resides in the inclusion of at least one boron-containing compound in one or both of the first and second polymeric layers in an amount sufficient to improve the interlayer adhesion between the first and second polymeric layers. Also provided is an improved curable coating composition used to form a multi-layer composite coating of two or more cured coating layers, at least one of which is formed from the thermosetting composition. Related methods and coated substrates are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

Reference is made to related U.S. patent application Ser. Nos. __/____,__/____, __/____ and __/____, filed concurrently herewith.

FIELD OF THE INVENTION

The present invention relates to multi-layer composites of two or morepolymeric layers, at least one of which is formed from a thermosettingcomposition. The composite comprising at least a first polymeric layerformed on a substrate and a second polymeric formed over at least aportion of the first polymeric layer, wherein in the absence of anadhesion promoting composition, the first polymeric layer and the secondpolymeric layer have poor interlayer adhesion. The present inventionalso relates to curable coating compositions used to form multi-layercomposites, to methods for improving the interlayer adhesion of suchmulti-layer composites and to coated substrates.

BACKGROUND OF THE INVENTION

Color-plus-clear coating systems involving the application of a coloredor pigmented basecoat to a substrate followed by application of atransparent or clearcoat over the basecoat have become increasinglypopular as original finishes for a number of consumer productsincluding, for example, automotive vehicles. The color-plus-clearcoatingsystems have outstanding appearance properties such as gloss anddistinctness of image, due in large part to the clearcoat. Suchcolor-plus-clearcoating systems have become popular for use withautomotive vehicles, aerospace applications, floor coverings such asceramic tiles and wood flooring, packaging coatings and the like.

Topcoat coating compositions, particularly those used to form thetransparent clearcoat in color-plus-clearcoating systems for automotiveapplications, are subject to defects that occur during the assemblyprocess as well as damage from numerous environmental elements. Suchdefects during the assembly process include paint defects in theapplication or curing of the basecoat or the clearcoat. Damagingenvironmental elements include acidic precipitation, exposure toultraviolet radiation from sunlight, high relative humidity and hightemperatures, defects due to contact with objects causing scratching ofthe coated surface, and defects due to impact with small, hard objectsresulting in chipping of the coating surface.

Further, elastomeric automotive parts and accessories, for example,elastomeric bumpers and body side moldings, are typically coated “offsite” and shipped to automobile assembly plants. The coatingcompositions applied to such elastomeric substrates are typicallyformulated to be very flexible so the coating can bend or flex with thesubstrate without cracking. To achieve the requisite flexibility,coating compositions for use on elastomeric substrates often areformulated to produce coatings with lower crosslink densities or toinclude flexibilizing adjuvants which act to lower the overall filmglass transition temperature (Tg). While acceptable flexibilityproperties can be achieved with these formulating techniques, they alsocan result in softer films that are susceptible to scratching.Consequently, great expense and care must be taken to package the coatedparts to prevent scratching of the coated surfaces during shipping toautomobile assembly plants.

U.S. Pat. No. 6,235,858 B1 discloses carbamate and/or urea functionalpolymers for use in coating compositions, especially clear coatingcompositions for color-plus-clear coating systems. Such polymers providecoatings with good resistance to damage caused by acidic precipitation.

U.S. Pat. No. 5,853,809 discloses clearcoats in color-plus-clear systemswhich have improved scratch resistance due to the inclusion in thecoating composition of inorganic particles such as colloidal silicaswhich have been surface modified with a reactive coupling agent viacovalent bonding.

A number of patents disclose the use of a surface active material, forexample, a polysiloxane, in coating compositions to improvemar-resistance of the cured coatings. U.S. Pat. Nos. 5,939,491 and6,225,434B1 disclose coating compositions comprising organicpolysiloxanes having reactive functional groups. These polysiloxanesprovide coatings with improved mar and scratch resistance.

A number of patents disclose the use of boric acid in polymericcompositions. For example, U.S. Pat. Nos. 5,951,747 and 6,059,867discloses the use of boric acid and borates in conjunction with asuccinate in non-chromate, corrosion-inhibiting coating compositions forimproved adhesion to metallic surfaces. Such compositions furtherinclude inhibitors such as phosphates, phosphosilicates, silicates,titanates, and zinc salts. U.S. Pat. No. 4,832,990 discloses a processfor improving adhesion of polyolefins to metal substrates comprisingmechanical cleaning of the metal surface, treating the metal surfacewith a water-alcohol solution containing an alkoxysilane and boric acid,thermally treating the acid treated substrate, and subsequently treatingthe substrate with a polyolefin-based composition comprising zeolitesand carbon black pigment. U.S. Pat. No. 5,073,455 discloses athermoplastic laminated film which has improved adhesion to hydrophilicpolymers, hydrophobic polymers and inorganic substances. The filmcomprise a base film of thermoplastic resin and a layer formed on thebase film comprising a composition of one or more of water-solubleresins, water emulsified resins and water-dispersible resins, and anorganic boron polymer or a mixture composed of an organic boron polymerand vinyl alcohol.

Other multi-layer composite coatings are commonplace in modern coatinglines. For example, a typical automotive coating system can include thesequential application of an electrodeposition primer, aprimer-surfacer, a color enhancing base coat, and a transparent topcoat. In some instances, the electrodeposition primer is applied over amill-applied weldable, thermosetting coating which has been applied tothe coiled steel metal substrate from which the automobile body (or bodyparts, such as fenders, doors and hoods) has been formed. Also, adhesivecoatings, for example, windshield adhesives, trim and molding adhesivesand structural adhesives are sometimes applied to the cured top coatswhere necessary. Due to these multi-layer composite coating processes,it is necessary that the previously applied coating layer have excellentintercoat or interlayer adhesion to the subsequently applied coatinglayer(s).

Although the aforementioned coating compositions exhibit improvementsfor acid etch resistance and mar and scratch resistance, suchcompositions may not be readily recoatable. That is, when a subsequentcoating is applied to the cured mar and scratch resistant coatingcomposition, the intercoat adhesion between the cured coating and thesubsequently applied coating can be quite poor.

For example, as mentioned above, on most vehicle coating lines thevehicle body is first given a corrosion inhibitive electrodepositableprimer coating commonly formed from a cationic electrodepositablecoating composition. This electrodeposition primer is fully cured and, aprimer-surfacer is typically applied to the cured electrodepositionprimer. The primer-surfacer serves to enhance chip resistance ofsubsequently applied top coatings as well as to ensure good appearanceof the top coatings. The electrodepositable primer must have excellentinterlayer, i.e., intercoat, adhesion to the subsequently appliedprimer-surfacer coating. The top coats, which can include a monocoats aswell as a color-plus-clear coating system, are then applied to the curedprimer-surfacer coating. While most top coats have excellent intercoatadhesion to the primer-surfacer coating, some top coating compositionsinherently may exhibit intercoat adhesion problems with someprimer-surfacer coatings.

Also, due to the resultant cost-savings, there is recent interest in theautomotive coatings market in eliminating the primer-surfacer stepaltogether. That is, the top coats can be directly applied to the curedelectrodeposition primer. In such modified coating processes, theelectrodeposition primer is required to meet stringent durability andappearance specifications. Moreover, the cured electrodepositable primermust have excellent intercoat adhesion to the subsequently applied topcoats (either monocoats or color coats of a color-plus-clear system).

On commercial automobile coating lines during application of the coatingsystem, certain portions of the line can experience occasional processproblems, for example, clearcoat applicator malfunctions, or curing ovenfaults where temperatures are out of specification. While the color coattypically is “flash cured” to drive off solvent, but not fully cure thecoating, once the clear coating has been applied, the color-plus-clearcoating system typically is given a full cure (e.g., 250° F. for 20minutes) to simultaneously cure both the base coat and the top coat. Ininstances where the clear coat application system is malfunctioning, theauto body with the applied color coat will continue through the clearcoat applicator station and into the clear coat curing oven, therebyfully curing the color coat. If this occurs, some automobilemanufacturers elect to reapply the color coat over the fully cured colorcoat prior to application of the clearcoat. In such situations, thefully cured color coat can have poor intercoat adhesion with thesubsequently applied color coat, even though the compositions may be thesame.

Also, windshields and other items such as trim moldings typically areaffixed to the body of a vehicle with an adhesive material, typically amoisture-cured material containing isocyanate group-containing polymers.Motor Vehicle Safety Standards (MVSS) require that these adhesives havecomplete adhesion to both the windshield and the coated substrate towhich they are applied. Similar adhesive compositions can be used asstructural adhesives as well. Such adhesives, for example, arecommercially available from Essex Specialty Products, Inc. of AubumHills, Mich. These adhesive products adhere well to many cured topcoating compositions used to coat vehicles such as automobiles. It isknown, however, that these adhesive materials often do not completelyadhere to some top coats, for example, those formed from coatingcompositions based on carbamate and/or urea containing polymers. Thisnecessitates the application of a primer coating to the cured carbamateand/or urea-based top coatings prior to application of the windshieldadhesive to ensure compliance with the aforementioned Motor VehicleSafety Standards. Such primer coatings are typically based onmoisture-curable polymers similar to those comprising the adhesive. Useof such primer coatings has proven to be effective, but primer coatingapplication adds an additional and expensive step to the windshieldand/or trim installation processes.

Moreover, as discussed previously, during the assembly process, theapplied color-plus-clear coating can include surface defects in theclear coat surface which requires repair. Some automobile manufacturerselect to remove the defect and recoat the repair area with the sameclear coat composition. In this instance, the cured clear coat must haveexcellent intercoat adhesion to the subsequently applied clear coat. Itis known, however, that some clear coats when cured have poor intercoatadhesion with the subsequently applied repair clear coat.

In view of the foregoing, there remains a need in the coating industryfor coating compositions which have improved properties such as acidetch resistance and mar and scratch resistance while maintainingexcellent intercoat or interlayer adhesion to subsequently appliedcoatings and/or adhesives.

Also, many adhesion promoters are known in the art. Such adhesionpromoters include, for example, phosphatized epoxy compounds, forexample, the reaction product formed from phosphoric acid and abisphenol A or hydrogenated bisphenol A diglycidyl ether. Typically,such adhesion promoters are useful for promoting adhesion of coatinglayers which contain them to a substrate, for example, a metallicsubstrate or an elastomeric substrate or to a previously applied coatinglayer. Also, such adhesion promoters can be used advantageously topromote cohesive integrity within a coating layer, for example, thecohesive integrity of a metal flake-containing basecoat. Further, it isknown that adhesion promoter compositions, such as a phosphate wipe oran adhesion-promoting primer, can be topically applied to a curedcoating to provide an adhesion promoting layer thereover, therebyimproving adhesion of a subsequently applied coating. This, however,necessitates an additional and costly coating step in the coatingapplication process. It is not known, however, to include an adhesionpromoter as a component in a coating composition which will migrateduring a curing reaction through the surrounding polymeric matrix to thesurface of the resultant coating thereby promoting the interlayer orintercoat adhesion between the resultant coating and a subsequentlyapplied coating.

As mentioned above, the surface of a coating can be modified by theinclusion of one or more surface active agents, for example, siliconeoils, siloxanes, and fluorsurfactants, in the coating compositions toimprove such properties as slip and mar resistance of such coatings.Typical surface active agents have solubility parameters or surfaceenergies which are sufficiently different from the coating compositions(i.e., the composition without the surface active agent) such that, whenincluded in the composition, the surface active agent can migrate orpartition to the surface region of the cured coating as the compositioncures. That is, the surface active agent is present at the surfaceregion of the resultant coating layer. While such surface-modifiedcoatings can exhibit improved slip and mar resistance, they often aredifficult to recoat. Hence, the interlayer or intercoat adhesion with asubsequently applied coating is poor, sometimes resulting indelamination.

It has now been found that by selecting adhesion promoting componentsand surface active agents such that the solubility parameter of thecoating composition containing both the adhesion promoting component andthe surface active agent is sufficiently different from that of ananalogous coating composition which does not contain the adhesionpromoting component and the surface active agent, that the adhesionpromoting component partitions to the surface region of the resultantcoating. This can result in a concentration of the adhesion promotingcomponent at the surface region which is greater than the concentrationin the interior or bulk region of the coating layer. This partitioningeffect of the adhesion promoting component can significantly increaseits effect in promoting the adhesion of the coating layer which containsthe adhesion promoter to a subsequently applied coating layer, as wellas to the substrate to which it is applied.

SUMMARY OF THE INVENTION

In one embodiment, the present invention is directed to an improvedmulti-layer composite of two or more polymeric layers at least one ofwhich is formed from a thermosetting composition. The compositecomprises at least a first polymeric layer formed on a substrate and asecond polymeric layer over at least a portion of the first polymericlayer, wherein in the absence of a boron-containing compound, the firstpolymeric layer and the second polymeric layer have poor interlayeradhesion. The improvement comprises the inclusion of at least oneboron-containing compound selected from boric acid, boric acidequivalents, and mixtures thereof in one or both of the first and secondpolymeric layers in an amount sufficient to improve the interlayeradhesion of the first polymeric layer and the second polymeric layer.

The present invention is also directed to an improved curable coatingcomposition used to form a multi-layer composite coating comprising twoor more cured coating layers. The multi-layer composite coatingcomprises at least a first coating layer formed on at least a portion ofa substrate and a second coating layer formed over at least a portion ofthe first coating layer, wherein one or both of the first and secondcoating layers is formed from the improved coating composition, andwherein in the absence of a boron-containing compound, the first coatinglayer and the second coating layer have poor interlayer adhesion. Theimprovement comprises the inclusion in the curable coating compositionof a boron-containing compound selected from at least one of boric acid,boric acid equivalents, and mixtures thereof in an amount sufficient toimprove the interlayer adhesion between the first coating layer and thesecond coating layer.

In a further embodiment, the present invention is directed to a methodfor improving the interlayer adhesion of a multi-layer compositecomprising two or more polymeric layers, at least one of which is formedfrom a thermosetting composition. The composite comprises at least afirst polymeric layer formed on at least a portion of a substrate and asecond polymeric layer formed over at least a portion of the firstpolymeric layer, wherein in the absence of a boron-containing compound,the first polymeric layer and the second polymeric layer have poorinterlayer adhesion. The improvement comprises the inclusion in one orboth of the polymeric layers of any of the aforementionedboron-containing compounds in an amount sufficient to improve theinterlayer adhesion of the first polymeric layer and the secondpolymeric layer.

In another embodiment, the present invention provides curable coatingcomposition formed from components comprising (A) at least onefilm-forming polymer comprising at least one reactive functional group;(B) at least one reactant comprising at least one functional group thatis reactive with the reactive functional group of the polymer (A); and(C)at least one compound selected from borates, aluminates, titanates,zirconates, silicates, siloxanes, silanes, and mixtures thereof, whereineach component is different.

Coated substrates are also provided.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Other than in the operating examples, or where otherwise indicated, allnumbers expressing quantities of ingredients, reaction conditions and soforth used in the specification and claims are to be understood as beingmodified in all instances by the term “about.” Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing specification and attached claims are approximations that mayvary depending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical values, however, inherently contain certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include all sub-ranges between andincluding the recited minimum value of 1 and the recited maximum valueof 10, that is, having a minimum value equal to or greater than 1 and amaximum value of equal to or less than 10.

In one embodiment, the present invention provides an improvedmulti-layer composite comprising at least a first polymeric layer and asecond polymeric layer formed over the first polymeric layer therebyforming an interface region there between. At least one of the polymericlayers is formed from a thermosetting composition comprising an adhesionpromoter composition. Tthe adhesion promoter composition comprises (1)at least one adhesion promoting component, and (2) at least one surfaceactive component. The improvement comprises the presence of the adhesionpromoting component (1) at the interface region.

In a further embodiment, the present invention is directed to animproved multi-layer composite comprising at least a first polymericlayer and a second polymeric layer formed over the first polymeric layerthereby forming an interface region there between. The first polymericlayer has a surface region and a bulk region and is formed from athermosetting composition. The thermosetting composition is formed fromthe following components: (A) at least one polymer comprising one ormore reactive functional groups selected from at least one of a hydroxylgroup and a carbamate group; (B) at least one curing agent selected fromat least one of an aminoplast resin, a polyisocyanate and a blockedisocyanate; and (C) at least one adhesion promoter compositioncomprising (1) at least one adhesion promoting component selected fromat least one of boric acid, boric acid equivalents, and mixturesthereof, and (2) at least one surface active component comprising aleast one polysiloxane comprising at least one of the followingstructural units (I):R¹ _(n)R² _(m)SiO_((4-n-m)/2)  wherein each R¹ is independently selected from H, a monovalenthydrocarbon group or a siloxane group; each R² independently is a groupcomprising at least one reactive functional group, typically OR′, whereR′ is H or an alkyl group having 1 to 20 carbon atoms; and m and n eachrepresent a positive number fulfilling the requirements of 0<m<4; 0<n<4;and 2<(m+n)<4. The improvement comprises the presence of the adhesionpromoting component (1) at the interface region.

The adhesion promoter composition comprises at least one adhesionpromoting component (1) and at least one surface active component (2).It should be understood that the adhesion promoter composition cancomprise the adhesion promoting component (1) and the surface activecomponent as separate components in an admixture; or the adhesionpromoter composition can comprise a reaction product formed from theadhesion promoting component (1) and the surface active component (2).Obviously, the adhesion promoter composition can comprise the abovedescribed reaction product formed from components (1) and (2), as wellas the component (1), and the component (2), all present as threeseparate ingredients.

In one embodiment of the present invention, the adhesion promotercomposition comprises an adhesion promoting component (1) which isselected from at least one of boron, aluminum, titanium, zirconium, andsilicon. Typically, the adhesion promoting component (1) comprises acompound selected from at least one of a borate, an aluminate, atitanate, a zirconate, a silicate, a siloxane, a silane and mixturesthereof. In one specific embodiment of the invention, the at least oneadhesion promoting component (1) is selected from at least one of aborate and an aluminate.

Examples of suitable borates are those discussed below in detail.Examples of titanates suitable for use in the compositions of thepresent invention include titanium isopropoxide, isopropyl triostearoyltitanate, dicyclo(dioct)pyrophosphato titanate, tetraisopropyldi(dioctyl)phosphito titanate. Suitable aluminates include aluminumalkoxides such as aluminum isoproxide, which is typically employed, andaluminum acetylacetonate, Exemplary of a suitable silicate is tetraethylorthosilicate. Suitable siloxanes include tetraisopropyldisiloxanes andtetramethylsiloxane. Suitable silanes include tetramethyl silyl ethers.In one embodiment of the present invention, a polysiloxane comprisingone or more hydroxyl functional groups is employed as the surface activecomponent (2). In one particular embodiment of the present invention,the adhesion promoting component (1) comprises an aluminum alkoxide,such as aluminum triisopropoxide, and the surface active component (2)comprises a polysiloxane comprising one or more hydroxyl groups.

Other materials suitable for use as the surface active component (2) areany of the surface active agents well known in the art. As used herein,by “surface active agent” is meant any material which tends to lower thesolid surface tension or surface energy of the “cured” composition orcoating. That is, the cured composition or coating formed from acomposition comprising a surface active agent has a lower solid surfacetension or surface energy than a cured coating formed from the analogouscomposition which does not contain the surface active agent.

For purposes of the present invention, solid surface tension can bemeasured according to the Owens-Wendt method using a Rame'-Hart ContactAngle Goniometer with distilled water and methylene iodide as reagents.Generally, a 0.02 cc drop of one reagent is placed upon the curedcoating surface and the contact angle and its complement are measuredusing a standard microscope equipped with the goniometer. The contactangle and its complement are measured for each of three drops. Theprocess is then repeated using the other reagent. An average value iscalculated for the six measurements for each of the reagents. The solidsurface tension is then calculated using the Owens-Wendt equation:{γ|(1+cos Φ)}/2=(γ|^(d)γ_(s) ^(d))^(1/2)+(γ|^(p)γ_(s) ^(p))^(1/2)where γ| is the surface tension of the liquid (methylene iodide=50.8,distilled water=72.8) and γ^(d) and γ^(p) are the dispersion and polarcomponents (methylene iodide γ^(d)=49.5, γ^(p)=1.3; distilled waterγ^(d)=21.8, γ^(p)=51.0); the values for Φ measured and the cos Φdetermined. Two equations are then setup, one for methylene iodide andone for water. The only unknowns are γ_(s) ^(d) and γ_(s) ^(p). The twoequations are then solved for the two unknowns. The two componentscombined represent the total solid surface tension.

The surface active component (2) can be selected from amphiphilic,reactive functional group-containing polysiloxanes such as are describedbelow, amphiphilic fluoropolymers, and mixtures of any of the foregoing.With reference to water-soluble or water-dispersible amphiphilicmaterials, the term “amphiphilic” means a polymer having a generallyhydrophilic polar end and a water-insoluble generally hydrophobic end.Nonlimiting examples of suitable functional group-containingpolysiloxanes for use as surface active agents include thosepolysiloxanes described above. Nonlimiting examples of suitableamphiphilic fluoropolymers include fluoroethylene-alkyl vinyl etheralternating copolymers (such as those described in U.S. Pat. No.4,345,057) available from Asahi Glass Company under the tradenameLUMIFLON; fluorosurfactants, such as the fluoroaliphatic polymericesters commercially available from 3M of St. Paul, Minn. under thetradename FLUORAD; functionalized perfluorinated materials, such as 1H,1H-perfluoro-nonanol commercially available from FluoroChem USA; andperfluorinated (meth)acrylate resins.

Nonlimiting examples of other adjuvant surface active agents suitablefor use in the composition or coating of the present invention caninclude anionic, nonionic and cationic surface active agents.

Nonlimiting examples of suitable anionic surface active agents includesulfates or sulfonates. Specific nonlimiting examples include higheralkyl mononuclear aromatic sulfonates such as the higher alkyl benzenesulfonates containing from 10 to 16 carbon atoms in the alkyl group anda straight- or branched-chain, e.g., the sodium salts of decyl, undecyl,dodecyl, tridecyl, tetradecyl, pentadecyl or hexadecyl benzene sulfonateand the higher alkyl toluene, xylene and phenol sulfonates; alkylnaphthalene sulfonate, and sodium dinonyl naphthalene sulfonate. Othernonlimiting examples of suitable anionic surface active agents includeolefin sulfonates, including long chain alkenylene sulfonates, longchain hydroxyalkane sulfonates, and mixtures of any of the foregoing.Nonlimiting examples of other sulfate or sulfonate detergents areparaffin sulfonates such as the reaction products of alpha olefins andbisulfites (e.g., sodium bisulfite). Also comprised are sulfates ofhigher alcohols, such as sodium lauryl sulfate, sodium tallow alcoholsulfate, or sulfates of mono- or di-glycerides of fatty acids (e.g.,stearic monoglyceride monosulfate), alkyl poly(ethoxy)ether sulfatesincluding, but not limited to, the sulfates of the condensation productsof ethylene oxide and lauryl alcohol (usually having 1-5 ethenoxy groupsper molecule); lauryl or other higher alkyl glyceryl ether sulfonates;aromatic poly(ethenoxy)ether sulfates including, but not limited to, thesulfates of the condensation products of ethylene oxide and nonyl phenol(usually having 1-20 oxyethylene groups per molecule). Furthernonlimiting examples include salts of sulfated aliphatic alcohol, alkylether sulfate or alkyl aryl ethoxy sulfate available from Rhone-Poulencunder the general tradename ABEX. Phosphate mono- or di-ester typeanionic surface active agents also can be used. These anionic surfaceactive agents are well known in the art and are commercially availableunder the general trade designation GAFAC from GAF Corporation and underthe general trade designation TRITON from Rohm & Haas Company.

Nonlimiting examples of nonionic surface active agents suitable for usein the cured composition or coating of the present invention includethose containing ether linkages and which are represented by thefollowing general formula: RO(R′O)_(n)H; wherein the substituent group Rrepresents a hydrocarbon group containing 6 to 60 carbon atoms, thesubstituent group R′ represents an alkylene group containing 2 or 3carbon atoms, and mixtures of any of the foregoing, and n is an integerranging from 2 to 100. Such nonionic surface active agents can beprepared by treating fatty alcohols or alkyl-substituted phenols with anexcess of ethylene or propylene oxide. The alkyl carbon chain maycontain from 14 to 40 carbon atoms and may be derived from a long chainfatty alcohol such as oleyl alcohol or stearyl alcohol. Nonionicpolyoxyethylene surface active agents of the type represented by theformula above are commercially available under the general tradedesignation SURFYNOL® from Air Products Chemicals, Inc.; PLURONIC® orTETRONIC® from BASF Corporation; TERGITOL® from Union Carbide; andSURFONIC® from Huntsman Corporation. Other nonlimiting examples ofsuitable nonionic surface active agents include block copolymers ofethylene oxide and propylene oxide based on a glycol such as ethyleneglycol or propylene glycol including, but not limited to, thoseavailable from BASF Corporation under the general trade designationPLURONIC®.

As indicated above, cationic surface active agents also can be used.Nonlimiting examples of cationic surface active agents suitable for usein the compositions of the present invention include acid salts of alkylamines such as ARMAC® HT, an acetic acid salt of n-alkyl amine availablefrom Akzo Nobel Chemicals; imidazoline derivatives such as CALGENE®C-100 available from Calgene Chemicals Inc.; ethoxylated amines oramides such as DETHOX® Amine C-5, a cocoamine ethoxylate available fromDeforest Enterprises; ethoxylated fatty amines such as ETHOX® TAMavailable from Ethox Chemicals, Inc.; and glyceryl esters such asLEXEMUL® AR, a glyceryl stearate/stearaidoethyl diethylamine availablefrom Inolex Chemical Co.

Other examples of suitable surface active agents can includepolyacrylates. Nonlimiting examples of suitable polyacrylates includehomopolymers and copolymers of acrylate monomers, for examplepolybutylacrylate and copolymers derived from acrylate monomers (such asethyl (meth)acrylate, 2-ethylhexylacrylate, butyl (meth)acrylate andisobutyl acrylate), and hydroxy ethyl(meth)acrylate and (meth)acrylicacid monomers. In one embodiment, the polyacrylate can have amino andhydroxy functionality. Suitable amino and hydroxyl functional acrylatesare disclosed in Example 26 below and in U.S. Pat. No. 6,013,733, whichis incorporated herein by reference. Another example of a useful aminoand hydroxyl functional copolymer is a copolymer of hydroxy ethylacrylate, 2-ethylhexylacrylate, isobutyl acrylate and dimethylaminoethylmethacrylate. In another embodiment, the polyacrylate can have acidfunctionality, which can be provided, for example, by including acidfunctional monomers such as (meth)acrylic acid in the components used toprepare the polyacrylate. In another embodiment, the polyacrylate canhave acid functionality and hydroxyl functionality, which can beprovided, for example, by including acid functional monomers such as(meth)acrylic acid and hydroxyl functional monomers such as hydroxyethyl (meth)acrylate in the components used to prepare the polyacrylate.

In one particular embodiment, the thermosetting composition used to formone or more of the polymeric layers is such that the free energy ofmixing value for an admixture of the adhesion promoter composition andthe analogous thermosetting composition which does not contain of theadhesion promoter composition is a positive value. In another embodimentof the present invention, the solubility parameter of the adhesionpromoter composition is sufficiently different from the solubilityparameter of the analogous thermosetting composition which does notcontain the adhesion promoter composition, such that the resultingthermodynamic interaction parameter value (_(χ)) for the admixture ofthe adhesion promoter composition and the thermosetting compositionwhich does not contain the adhesion promoter composition is 0.5 orgreater.

The “free energy of mixing” is defined as ΔG=ΔH−TΔS, where G is theGibb's free energy, H is enthalpy, S is entropy and T is temperature. Insimple terms, when the free energy of mixing (ΔG) of two components is apositive value, the two components are immiscible and will phaseseparate. For example, in the instance where a coating compositioncontains these two substantially immiscible components, when applied asa coating layer one component will tend to migrate or partition to thesurface region of the coating layer while the other will remain in thebulk region. Also, ΔG for a binary mixture containing a component 1 anda component 2 may be defined by the following equation:ΔG=RT[(n ₁ ln X ₁ +n ₂ln X ₂)_(+χ) n ₁ X ₂]where R is the gas constant, T is temperature, X is the volume fractionof component 1 or 2, N is the number of particles, and _(χ) (“chi”)represents the thermodynamic interaction parameter. The thermodynamicinteraction parameter (_(χ) or “chi”) is defined as the difference inthe energy of mixing of components 1 and 2. This can be represented bythe following equation:χ=(ΔE _(mix) /RT)V _(m)where V_(m) is the average molar volume (“reference segment volume”) andR and T are defined above. “Chi” may also be defined as the differencein solubility parameter (SP) of two materials._(χ) =V _(m) (δ₁−δ₂)² /RTwhere δ is the Hildebrand solubility parameter. The solubility parametermay be computed from a value known as the cohesive energy density(“ced”) of a material. The “ced” is related to the heat of vaporizationof a material, that is, how much energy is required to remove a singlemolecule from the bulk. For polymeric systems, such as a coatingcomposition, where the assumption that the entropy of mixing isexceedingly small, the free energy expressions reduce to the energy ofmixing itself, that is ΔG=ΔH, and a theoretical critical point existswhere two materials become immiscible (phase separate) when “chi” isgreater than 0.5. For regular solutions, (low molecular weight species)this critical point has a value of 2.0.

To summarize, from first principles, the “ced” for a bulk material canbe computed. The “ced” is directly related to the solubility parameter(δ) as indicated above. The thermodynamic interaction parameter “chi”(_(χ)) can be computed from the differences in the solubility parameter(δ) for each of the two materials. “Chi” along with relative fractionsof materials in a mixture may be used to compute the free energy ofmixing (ΔG). If ΔG is a positive value, the mixture is thermodynamicallyunstable and phase separation will occur. Critical points for thiscondition are values of “chi” 0.5 and greater for higher molecularweight materials such as the polymeric components of a resinous bindersystem, and 2.0 for smaller molecules. Flory, Paul J., Principles ofPolymer Chemistry, Cornell University Press (1953), Chapters XII andXIII; Polymer User Guide, September 1996, Molecular Simulations, Inc.,San Diego, Calif.;Nicolaides, D., Parameterisation for MesoscaleModeling, Molecular Simulations, Inc.

Without intending to be bound by any theory, it is believed that by suchphase separation discussed above, the adhesion promoting component (1)can be present in the interface region between the first polymer layerand the second polymer layer, thereby providing improved interlayeradhesion between the two.

In one embodiment of the present invention, the first polymeric layer isformed from the thermosetting composition, typically over a substrate,and comprises a surface region and a bulk region. As used herein“surface region” of the cured thermosetting composition (or of theresultant polymeric layer) means the region which is generally parallelto the exposed air-surface interface of the cured composition (typicallyformed on a substrate) and which has thickness generally extendingperpendicularly from the surface of the cured polymeric layer to a depthranging from at least 20 nanometers to 200 nanometers beneath theexposed surface. In certain embodiments, this thickness of the surfaceregion ranges from at least 20 nanometers to 100 nanometers, and canrange from at least 20 nanometers to 50 nanometers. As used herein,“bulk region” of the cured thermosetting composition (or the resultantpolymeric layer) means the region which extends beneath the surfaceregion and which is generally parallel to the surface of the substrateto which the composition has been applied. The bulk region has athickness extending from its interface with the surface region throughthe cured composition to the substrate or polymeric layer beneath thecured composition.

In another embodiment of the present invention, the free energy ofmixing value of an admixture of the adhesion promoter composition andthe thermosetting composition without the adhesion promoter compositionis a positive value such that the adhesion promoting component (1) ispartitioned within the first polymeric layer to provide a concentrationof the adhesion promoting component (1) at the surface region which isgreater than the concentration of the adhesion promoting component (1)within the bulk region of the polymeric layer.

In yet another embodiment of the present invention, the solubilityparameter of the adhesion promoter composition is sufficiently differentfrom the solubility parameter of the thermosetting composition withoutthe adhesion promoter composition, such that the thermodynamicinteraction parameter value for the admixture of the adhesion promotercomposition and the thermosetting composition without the adhesionpromoter composition is greater than 0.5, thereby causing the adhesionpromoting component (1) to partition within the first polymeric layer toprovide a concentration of the adhesion promoting component (1) at thesurface region which is greater than the concentration of the adhesionpromoting component (1) in the bulk region of the first polymeric layer.

As previously mentioned, in one embodiment, the present inventionprovides an improved multi-layer composite of two or more polymericlayers at least one of which is formed from a thermosetting composition.The composite comprises at least a first polymeric layer formed on asubstrate and a second polymeric layer over at least a portion of saidfirst polymeric layer, wherein in the absence of an adhesion promotercomposition, typically boron-containing compound the first polymericlayer and the second polymeric layer have poor interlayer adhesion. Theimprovement comprises the inclusion of at least one boron-containingcompound selected from boric acid, boric acid equivalents, and mixturesthereof in one or both of the first and second polymeric layers in anamount sufficient to improve the interlayer adhesion of the first andsecond polymeric layers.

It should be understood that the composite of the present invention cancomprise only two polymeric layers, wherein the first polymeric layer isformed on at least a portion of a substrate and the second polymericlayer is formed over at least a portion of the first polymeric layer.Alternatively, the composite of the present invention can comprise thefirst polymeric layer over at least a portion of a substrate, and thesecond polymeric layer formed over at least a portion of the firstpolymeric layer, where there are one or more subsequent polymeric layersformed over at least a portion of the second polymeric layer.

For example, the first polymeric layer can comprise a primer-surfacercoating and the second polymeric layer can comprise a color-enhancingbase coating to which has been subsequently applied a transparent topcoat. Also, the first polymeric layer can comprise an electrodepositableprimer coating and the second polymeric layer can comprise aprimer-surfacer coating to which has been subsequently applied anappearance enhancing monocoat or a color-plus-clear coating system.Additionally, the first polymeric layer can comprise a transparent clearcoat (as the clear coat in a color-plus-clear coating system) and thesecond polymeric layer can comprise a repair clear coat.

Also, it should be understood that as used herein, a polymeric layer orcomposition formed “over” at least a portion of a “substrate” refers toa polymeric layer or composition formed directly on at least a portionof the substrate surface, as well as a polymeric layer or compositionformed over any coating or adhesion promoter material which waspreviously applied to at least a portion of the substrate.

That is, the “substrate” upon which the first polymeric layer has beenformed can comprise a metallic or elastomeric substrate to which one ormore coating layers have been previously applied. For example, the“substrate” can comprise a metallic substrate and a weldable primercoating over at least a portion of the substrate surface, and the firstpolymeric layer can comprise an electrodepositable primer coating.Likewise, the “substrate” can comprise a metallic substrate having anelectrodepositable primer formed over at least a portion thereof, and aprimer-surfacer coating over at least a portion of theelectrodepositable primer. The first polymeric layer can comprise, forexample, a pigmented base coat over at least a portion of thismultli-layer “substrate”, and the second polymeric layer can comprise apigment-free top coat formed over at least a portion of the pigmentedbase coat.

At least one of the first and second polymeric layers is formed from athermosetting composition. In the multi-layer composite of the presentinvention, the first polymeric only can comprise a thermosettingcomposition, the second layer only can comprise a thermosettingcomposition, or, alternatively both the first and second polymericlayers can comprise a thermosetting composition. In the latter instance,the thermosetting composition from which the first polymeric layer isformed and the thermosetting composition from which the second polymericlayer is formed can be the same or different thermosetting composition.

In one embodiment of the present invention, both the first polymericlayer and the second polymeric layer are formed from a thermosettingcomposition. In another embodiment, the thermosetting compositioncomprises a curable coating composition as described below.

As used herein, by “thermosetting composition” is meant one which “sets”irreversibly upon curing or crosslinking, wherein the polymer chains ofthe polymeric components are joined together by covalent bonds. Thisproperty is usually associated with a cross-linking reaction of thecomposition constituents often induced by heat or radiation. Hawley,Gessner G., The Condensed Chemical Dictionary, Ninth Edition., page 856;Surface Coatings, vol. 2, Oil and Colour Chemists' Association,Australia, TAFE Educational Books (1974). Once cured or crosslinked, athermosetting composition will not melt upon the application of heat andis insoluble in solvents. By contrast, a “thermoplastic composition”comprises polymeric components which are not joined by covalent bondsand thereby can undergo liquid flow upon heating and are soluble insolvents. Saunders, K. J., Organic Polymer Chemistry, pp. 4142, Chapmanand Hall, London (1973).

In one embodiment of the present invention, the substrate can comprise ametallic substrate. Examples of suitable metallic substrates can includeferrous metals and non-ferrous metals. Suitable ferrous metals includeiron, steel, and alloys thereof. Non-limiting examples of useful steelmaterials include cold-rolled steel, galvanized (zinc coated) steel,electrogalvanized steel, stainless steel, pickled steel, GALVANNEAL®,GALVALUME®, and GALVAN® zinc-aluminum alloys coated upon steel, andcombinations thereof. Useful non-ferrous metals include aluminum, zinc,magnesium and alloys thereof. Combinations or composites of ferrous andnon-ferrous metals can also be used.

In another embodiment of the present invention, the substrate cancomprise an elastomeric substrate. Suitable elastomeric substrates caninclude any of the thermoplastic or thermoset synthetic materials wellknown in the art. Nonlimiting examples of suitable flexible elastomericsubstrate materials include polyethylene, polypropylene, thermoplasticpolyolefin (“TPO”), reaction injected molded polyurethane (“RIM”) andthermoplastic polyurethane (“TPU”).

Nonlimiting examples of thermoset materials useful as substrates inconnection with the present invention include polyesters, epoxides,phenolics, polyurethanes such as “RIM” thermoset materials, and mixturesof any of the foregoing. Nonlimiting examples of suitable thermoplasticmaterials include thermoplastic polyolefins such as polyethylene,polypropylene, polyamides such as nylon, thermoplastic polyurethanes,thermoplastic polyesters, acrylic polymers, vinyl polymers,polycarbonates, acrylonitrile-butadiene-styrene (“ABS”) copolymers,ethylene propylene diene terpolymer (“EPDM”) rubber, copolymers, andmixtures of any of the foregoing.

If desired, the polymeric substrates described above can have anadhesion promoter present on the surface of the substrate over which anyof a number of coating compositions (including the coating compositionsof the present invention as described below) can be applied. Tofacilitate adhesion of organic coatings to polymeric substrates, thesubstrate can be pretreated using an adhesion promoter layer or tiecoat, e.g., a thin layer 0.25 mils (6.35 microns) thick, or by flame orcorona pretreatment.

Suitable adhesion promoters for use over polymeric substrates includechlorinated polyolefin adhesion promoters such as are described in U.S.Pat. Nos. 4,997,882; 5,319,032; and 5,397,602, incorporated by referenceherein. Other useful adhesion promoting coatings are disclosed in U.S.Pat. Nos. 6,001,469 (a coating composition containing a saturatedpolyhydroxylated polydiene polymer having terminal hydroxyl groups),5,863,646 (a coating composition having a blend of a saturatedpolyhydroxylated polydiene polymer and a chlorinated polyolefin) and5,135,984 (a coating composition having an adhesion promoting materialobtained by reacting a chlorinated polyolefin, maleic acid anhydride,acryl or methacryl modified hydrogenated polybutadiene containing atleast one acryloyl group or methacryloyl group per unit molecule, andorganic peroxide), which are incorporated herein by reference.

When the substrates are used as components to fabricate automotivevehicles (including, but not limited to, automobiles, trucks andtractors) they can have any shape, and can be selected from the metallicand/or flexible substrates described above. Typical shapes of automotivebody components can include body side moldings, fenders, bumpers, hoods,and trim for automotive vehicles.

Also, as mentioned above, in the absence of an adhesion promotingcomposition, typically a boron-containing compound, the first polymericlayer and said second polymeric layer have poor interlayer adhesion.That is, the second polymeric layer, in the absence of aboron-containing compound present in either of the first polymeric layeror the second polymeric layer, the two layers have poor interlayer(i.e., intercoat) adhesion. As used herein, by “poor interlayeradhesion” is meant that the second polymeric layer will havedelamination or adhesion loss from the first polymeric layer sufficientto be given a rating of 3 or lower, as determined in accordance withASTM-D 3359-97, method B, using the rating scale specified therein.

The improvement comprises the inclusion of an adhesion promotingcomposition, typically a boron-containing compound, in one or both ofthe first polymeric layer and the second polymeric layer in an amountsufficient to improve the interlayer adhesion of the first polymericlayer and the second polymeric layer. The boron-containing compound canbe present in the first polymeric layer only, the second polymeric layeronly, or, alternatively, in both the first polymeric layer and thesecond polymeric layer. In one embodiment of the present invention, theboron-containing compound is present in the first polymeric layer.

Also, it should be understood that the adhesion promoter, for example, aboron-containing compound, can be present in any of the polymeric layerscomprising the substrate over at least a portion of which is formed thefirst polymeric layer, as well as any of the polymeric layers that canbe subsequently formed over at least a portion of the second polymericlayer.

In the multi-layer composite of the present invention, theboron-containing compound can comprise a compound selected from boricacid, boric acid equivalents, and mixtures thereof.

As used herein, in the specification and in the claims, by “boric acidequivalents” is meant any of the numerous boron-containing compoundswhich can hydrolyze in aqueous media to form boric acid. As used herein,by “boric acid equivalents” is meant any of the numerousboron-containing compounds which can hydrolyze in aqueous media to formboric acid. Specific, but non-limiting examples of boric acidequivalents include boron oxides, for example, B₂O₃; boric acid esterssuch as those obtained by the reaction of boric acid with an alcohol orphenol, for example, trimethyl borate, triethyl borate, tri-n-propylborate, tri-n-butyl borate, triphenyl borate, triisopropyl borate,tri-t-amyl borate, triphenylborate, trimethoxyboroxine,tri-2-cyclohexylcyclohexyl borate, triethanolamine borate,triisopropylamine borate, mannitol borate, glycerol borate andtriisopropanolamine borate.

Additionally, other amino-containing borates and tertiary amine salts ofboric acid may be useful. Such boron-containing compounds include, butare not limited to,2-(beta-dimethylaminoisopropoxy)-4,5-dimethyl-1,3,2-dioxaborolane,2-(beta-diethylaminoethoxy)4,4,6-trimethyl-1,3,2-d ioxaborinane,2-(beta-dimethylaminoethoxy)-4,4,6-trimethyl-1,3,2-dioxaborinane,2-(betha-diisopropylaminoethoxy-1,3,2-dioxaborinane,2-(beta-dibutylaminoethoxy)-4-methyl-1,3,2-dioxaborinane,2-(gamma-dimethylaminopropoxy)-1,3,6,9-tetrapxa-2-boracycloundecane, and2- (beta-dimethylaminoethoxy)-4,4-(4-hydorxybutyl)-1,3,2-dioxaborolane.

Boric acid equivalents can also include metal salts of boric acid (i.e.,metal borates) provided that such metal borates can readily dissociatein aqueous media to form boric acid. Suitable examples of metal boratesinclude, for example, calcium borate, potassium borates such aspotassium metaborate, potassium tetraborate, potassium pentaborate,potassium hexaborate, and potassium octaborate, sodium borates such assodium perborate, sodium metaborate, sodium diborate, sodiumtetraborate, sodium pentaborate, sodium perborate, sodium hexaborate,and sodium octaborate, Likewise, ammonium borates can be useful.

Suitable boric acid equivalents can also include organic oligomeric andpolymeric compounds comprising boron-containing moieties. Suitableexamples include polymeric borate esters, such as those formed byreacting an active hydrogen-containing polymer, for example, a hydroxylfunctional group-containing acrylic polymer or polysiloxane polymer,with boric acid and/or a borate ester to form a polymer having borateester groups.

Polymers suitable for this purpose can include any of a variety ofactive hydrogen-containing polymers such as those selected from at leastone of acrylic polymers, polyester polymers, polyurethane polymers,polyether polymers and silicon-based polymers. As used herein, by“silicon-based polymers” is meant a polymer comprising one or more —SiO—units in the backbone. Such silicon-based polymers can include hybridpolymers, such as those comprising organic polymeric blocks with one ormore —SiO— units in the backbone.

Examples of active hydrogen-containing polymers suitable for thispurpose include polymers comprising functional groups selected from atleast one of a hydroxyl group, an amine group, an epoxy group, acarbamate group, a urea group, and a carboxylic acid group. In aparticular embodiment of the present invention, the boron-containingcompound is formed by reacting boric acid and/or a borate ester with atleast one polymer selected from an acrylic polyol, a polyester polyol, apolyurethane polyol, a polyether polyol, a polysiloxane polyol andmixtures thereof.

In one embodiment of the present invention, the boron-containingcompound comprises a polysiloxane borate ester formed from reactants (A)at least one polysiloxane comprising at least one of the followingstructural units (I):R¹ _(n)R² _(m)SiO_((4-n-m)/2)  (I)wherein each R¹, which may be identical or different, represents H, OH,a monovalent hydrocarbon group or a monovalent siloxane group; each R²,which may be identical or different, represents a group comprising atleast one reactive functional group, wherein m and n fulfill therequirements of O<n<4, 0<m<4 and 2≦(m+n)<4; and (B) at least oneboron-containing compound selected from at least one of boric acid, aboric acid equivalent, and mixtures thereof.

It should be understood that the “at least one polysiloxane comprisingat least one structural unit (I)” above is a polymer that contains atleast two Si atoms per molecule. As used herein, the term “polymer” inmeant to encompass oligomer, and includes without limitation bothhomopolymers and copolymers. It should also be understood that the atleast one polysiloxane can include linear, branched, dendritic or cyclicpolysiloxanes.

Moreover, as used herein, “formed from” denotes open, e.g.,“comprising,” claim language. As such, it is intended that a composition“formed from” a list of recited components be a composition comprisingat least these recited components, and can further comprise other,nonrecited components, during the composition's formation.

Also, as used herein, the term “reactive” refers to a functional groupthat forms a covalent bond with another functional group underconditions sufficient to cure the composition.

As used herein, the phrase “each component is different” refers tocomponents which do not have the same chemical structure as othercomponents in the composition.

Each of m and n depicted in the at least one structural unit (I) abovefulfill the requirements of 0<n<4, 0<m<4 and 2≦(m+n)<4. When (m+n) is 3,the value represented by n can be 2 and the value represented by m is 1.Likewise, when (m+n) is 2, the value represented by each of n and m is1.

As used herein, the term “cure” as used in connection with acomposition, e.g., “composition when cured,” shall mean that anycrosslinkable components of the composition are at least partiallycrosslinked. In certain embodiments of the present invention, thecrosslink density of the crosslinkable components, i.e., the degree ofcrosslinking, ranges from 5% to 100% of complete crosslinking. In otherembodiments, the crosslink density ranges from 35% to 85% of fullcrosslinking. In other embodiments, the crosslink density ranges from50% to 85% of full crosslinking. One skilled in the art will understandthat the presence and degree of crosslinking, i.e., the crosslinkdensity, can be determined by a variety of methods, such as dynamicmechanical thermal analysis (DMTA) using a TA Instruments DMA 2980 DMTAanalyzer conducted under nitrogen. This method determines the glasstransition temperature and crosslink density of free films of coatingsor polymers. These physical properties of a cured material are relatedto the structure of the crosslinked network.

As used herein, a “monovalent hydrocarbon group” means a monovalentgroup having a backbone repeat unit based exclusively on carbon. As usedherein, “monovalent” refers to a substituent group that, as asubstituent group, forms only one single, covalent bond. For example, amonovalent group on the at least one polysiloxane will form one singlecovalent bond to a silicon atom in the backbone of the at least onepolysiloxane polymer. As used herein, “hydrocarbon groups” are intendedto encompass both branched and unbranched hydrocarbon groups.

Thus, when referring to a “monovalent hydrocarbon group,” thehydrocarbon group can be branched or unbranched, acyclic or cyclic,saturated or unsaturated, or aromatic, and can contain from 1 to 24 (orin the case of an aromatic group from 3 to 24) carbon atoms. Nonlimitingexamples of such hydrocarbon groups include alkyl, alkoxy, aryl,alkaryl, and alkoxyaryl groups. Nonlimiting examples of lower alkylgroups include, for example, methyl, ethyl, propyl, and butyl groups. Asused herein, “lower alkyl” refers to alkyl groups having from 1 to 6carbon atoms. One or more of the hydrogen atoms of the hydrocarbon canbe substituted with heteroatoms. As used herein, “heteroatoms” meanselements other than carbon, for example, oxygen, nitrogen, and halogenatoms.

As used herein, “siloxane” means a group comprising a backbonecomprising two or more —SiO— groups. For example, the siloxane groupsrepresented by R¹, which is discussed above, and R, which is discussedbelow, can be branched or unbranched, and linear or cyclic. The siloxanegroups can be substituted with pendant organic substituent groups, forexample, alkyl, aryl, and alkaryl groups. The organic substituent groupscan be substituted with heteroatoms, for example, oxygen, nitrogen, andhalogen atoms, reactive functional groups, for example, those reactivefunctional groups discussed above with reference to R², and mixtures ofany of the foregoing.

In one embodiment, the at least one polysiloxane (A), which is used toform the polysiloxane borate ester, comprises at least two reactivefunctional groups. The at least one polysiloxane can have a reactivegroup equivalent weight ranging from 50 to 1000 mg per gram of the atleast one polysiloxane. In one embodiment, the at least one polysiloxanehas a hydroxyl group equivalent weight ranging from 50 to 1000 mg KOHper gram of the at least one polysiloxane. In another embodiment, the atleast one polysiloxane has a hydroxyl group equivalent weight rangingfrom 100 to 300 mg KOH per gram of the at least one polysiloxane, whilein another embodiment, the hydroxyl group equivalent weight ranges from100 to 500 mg KOH per gram.

In another embodiment, R² (see structural unit I above), which may beidentical or different, represents a group comprising at least onereactive functional group selected from a hydroxyl group, a carboxylgroup, an isocyanate group, a blocked isocyanate group, a primary aminegroup, a secondary amine group, an amide group, a carbamate group, aurea group, a urethane group, a vinyl group, an unsaturated ester groupsuch as an acrylate group and a methacrylate group, a maleimide group, afumarate group, an onium salt group such as a sulfonium group and anammonium group, an anhydride group, a hydroxy alkylamide group, and anepoxy group.

In another embodiment, the at least one R² group represents a groupcomprising at least one reactive functional group selected from ahydroxyl group and a carbamate group. In yet another embodiment, the atleast one R² group represents a group comprising at least two reactivefunctional groups selected from a hydroxyl group and a carbamate group.In another embodiment, the at least one R² group represents a groupcomprising an oxyalkylene group and at least two hydroxyl groups.

In one embodiment, the at least one polysiloxane (A), which is used toform the polysiloxane borate ester, has the following structure (II) or(III):

wherein: m has a value of at least 1; m′ ranges from 0 to 75; n rangesfrom 0 to 75; n′ ranges from 0 to 75; each R, which may be identical ordifferent, is selected from H, OH, a monovalent hydrocarbon group, amonovalent siloxane group, and mixtures of any of the foregoing; and—R^(a) comprises the following structure (IV):—R³—X  (IV)wherein —R³ is selected from an alkylene group, an oxyalkylene group, analkylene aryl group, an alkenylene group, an oxyalkenylene group, and analkenylene aryl group; and X represents a group which comprises at leastone reactive functional group selected from a hydroxyl group, a carboxylgroup, an isocyanate group, a blocked isocyanate group, a primary aminegroup, a secondary amine group, an amide group, a carbamate group, aurea group, a urethane group, a vinyl group, an unsaturated ester groupsuch as an acrylate group and a methacrylate group, a maleimide group, afumarate group, an onium salt group such as a sulfonium group and anammonium group, an anhydride group, a hydroxy alkylamide group, and anepoxy group.

In one embodiment of the present invention, X represents a group whichcomprises at least one reactive functional group selected from ahydroxyl group, a carboxyl group, a primary amine group, a secondaryamine group, an amide group, a carbamate group, a urea group, ananhydride group, a hydroxy alkylamide group, and an epoxy group.

As used herein, “alkylene” refers to an acyclic or cyclic, saturatedhydrocarbon group having a carbon chain length of from C₂ to C₂₅.Nonlimiting examples of suitable alkylene groups include, but are notlimited to, those derived from propenyl, 1-butenyl, 1-pentenyl,1-decenyl, and 1-heneicosenyl, such as, for example (CH₂)₃, (CH₂)₄,(CH₂)₅, (CH₂)₁₀, and (CH₂)₂₃, respectively, as well as isoprene andmyrcene.

As used herein, “oxyalkylene” refers to an alkylene group containing atleast one oxygen atom bonded to, and interposed between, two carbonatoms and having an alkylene carbon chain length of from C₂ to C₂₅.Nonlimiting examples of suitable oxyalkylene groups include thosederived from trimethylolpropane monoallyl ether, trimethylolpropanediallyl ether, pentaerythritol monoallyl ether, polyethoxylated allylalcohol, and polypropoxylated allyl alcohol, such as—(CH₂)₃OCH₂C(CH₂OH)₂(CH₂CH₂—).

As used herein, “alkylene aryl” refers to an acyclic alkylene groupsubstituted with at least one aryl group, for example, phenyl, andhaving an alkylene carbon chain length of C₂ to C₂₅. The aryl group canbe further substituted, if desired. Nonlimiting examples of suitablesubstituent groups for the aryl group include, but are not limited to,hydroxyl groups, benzyl groups, carboxylic acid groups, and aliphatichydrocarbon groups. Nonlimiting examples of suitable alkylene arylgroups include, but are not limited to, those derived from styrene and3-isopropenyl-∝,∝-dimethylbenzyl isocyanate, such as —(CH₂)₂C₆H₄— and—CH₂CH(CH₃)C₆H₃(C(CH₃)₂(NCO). As used herein, “alkenylene” refers to anacyclic or cyclic hydrocarbon group having one or more double bonds andhaving an alkenylene carbon chain length of C₂ to C₂₅. Nonlimitingexamples of suitable alkenylene groups include those derived frompropargyl alcohol and acetylenic diols, for example,2,4,7,9-tetramethyl-5-decyne-4,7-diol which is commercially availablefrom Air Products and Chemicals, Inc. of Allentown, Pennsylvania asSURFYNOL 104.

Formulae (II) and (III) are diagrammatic, and are not intended to implythat the parenthetical portions are necessarily blocks, although blocksmay be used where desired. In some cases the polysiloxane may comprise avariety of siloxane units. This is increasingly true as the number ofsiloxane units employed increases and especially true when mixtures of anumber of different siloxane units are used. In those instances where aplurality of siloxane units are used and it is desired to form blocks,oligomers can be formed which can be joined to form the block compound.By judicious choice of reactants, compounds having an alternatingstructure or blocks of alternating structure may be used.

In one embodiment of the present invention the substituent R³ representsan oxyalkylene group. In another embodiment, R³ represents anoxyalkylene group, and X represents a group which comprises at least tworeactive functional groups.

In another embodiment of the present invention where the at least onepolysiloxane (A) has the structure (II) or (III) described above, (n+m)ranges from 2 to 9. In yet another embodiment where the at least onepolysiloxane have the structure (II) or (III) described above, (n+m)ranges from 2 to 3. In another embodiment, where the at least onepolysiloxane have the structure (II) or (III) described above, (n′+m′)ranges from 2 to 9. In another embodiment where the at least onepolysiloxane has the structure (II) or (III) described above, (n′+m′)ranges from 2 to 3.

In yet another embodiment of the present invention, the substituent Xrepresents a group comprising at least one reactive functional groupselected from a hydroxyl group and a carbamate group. In anotherembodiment, the substituent X represents a group which comprises atleast two hydroxyl groups. In yet another embodiment, X represents agroup which comprises at least one group selected from H, amonohydroxy-substituted organic group, and a group having the followingstructure (V):R⁴—(—CH₂—OH)_(p)  (V)wherein the substituent group R⁴ represents —CH₂—C—R³ when p is 2 andthe substituent group R³ represents a C₁ to C₄ alkylene group, or thesubstituent group R⁴ represents —CH₂—C— when p is 3, wherein at least aportion of X represents a group having the structure (V). In anotherembodiment, where the polysiloxane (A) has the structure (I) or (II)described above, m is 2 and p is 2.

In another embodiment of the present invention, the polysiloxane (A) isformed from at least the following reactants: (i) at least onepolysiloxane of the formula (VI):

wherein each substituent group R, which may be identical or different,represents a group selected from H, OH, a monovalent hydrocarbon group,a monovalent siloxane group, and mixtures of any of the foregoing; atleast one of the groups represented by R is H, and n′ ranges from 0 to100, also can range from 0 to 10, and can further range from 0 to 5,such that the percent of SiH content of the polysiloxane ranges from 2to 50 percent, and can range from 5 to 25 percent; and (ii) at least onemolecule which comprises at least functional group selected from ahydroxyl group, a carboxyl group, an isocyanate group, a blockedisocyanate group, a primary amine group, a secondary amine group, anamide group, a carbamate group, a urea group, a urethane group, a vinylgroup, an unsaturated ester group such as an acrylate group and amethacrylate group, a maleimide group, a fumarate group, an onium saltgroup such as a sulfonium group and an ammonium group, an anhydridegroup, a hydroxy alkylamide group, and an epoxy group and at least oneunsaturated bond capable of undergoing a hydrosilylation reaction. Inanother embodiment, the at least one functional group comprises hydroxylgroups.

It should be appreciated that the various R groups can be the same ordifferent, and, in certain embodiments, the R groups will be entirelymonovalent hydrocarbon groups or will be a mixture of different groupssuch as, for example, monovalent hydrocarbon groups and hydroxyl groups.

In another embodiment, this reaction product is ungelled. As usedherein, “ungelled” refers to a reaction product that is substantiallyfree of crosslinking and has an intrinsic viscosity when dissolved in asuitable solvent, as determined, for example, in accordance withASTM-D1795 or ASTM-D4243. The intrinsic viscosity of the reactionproduct is an indication of its molecular weight. A gelled reactionproduct, on the other hand, since it is of an extremely high molecularweight, will have an intrinsic viscosity too high to measure. As usedherein, a reaction product that is “substantially free of crosslinking”refers to a reaction product that has a weight average molecular weight(Mw), as determined by gel permeation chromatography, of less than1,000,000.

It also should be noted that the level of unsaturation contained inreactant (ii) above, can be selected to obtain an ungelled reactionproduct. In other words, when a polysiloxane containing silicon hydride(i) having a higher average value of Si—H functionality is used,reactant (ii) can have a lower level of unsaturation. For example, thepolysiloxane containing silicon hydride (i) can be a low molecularweight material where n′ ranges from 0 to 5 and the average value ofSi—H functionality is two or less. In this case, reactant (ii) cancontain two or more unsaturated bonds capable of undergoinghydrosilylation reaction without the occurrence of gelation.

Nonlimiting examples of polysiloxanes containing silicon hydride (i)include 1,1,3,3-tetramethyl disiloxane where n′ is 0 and the averageSi—H functionality is two; and polymethyl polysiloxane containingsilicon hydride, where n′ ranges from 4 to 5 and the average Si—Hfunctionality is approximately two, such as is commercially availablefrom BASF Corporation as MASILWAX BASE®.

Materials for use as reactant (ii) above can include hydroxyl functionalgroup-containing allyl ethers such as those selected fromtrimethylolpropane monoallyl ether, pentaerythritol monoallyl ether,trimethylolpropane diallyl ether, polyoxyalkylene alcohols such aspolyethoxylated alcohol, polypropoxylated alcohol, and polybutoxylatedalcohol, undecylenic acid-epoxy adducts, allyl glycidyl ether-carboxylicacid adducts, and mixtures of any of the foregoing. Mixtures of hydroxylfunctional polyallyl ethers with hydroxyl functional monoallyl ethers orallyl alcohols are suitable as well. In certain instances, reactant (ii)can contain at least one unsaturated bond in a terminal position.Reaction conditions and the ratio of reactants (i) and (ii) are selectedso as to form the desired functional group.

The hydroxyl functional group-containing polysiloxane (A) can beprepared by reacting a polysiloxane containing hydroxyl functionalgroups with an anhydride to form the half-ester acid group underreaction conditions that favor only the reaction of the anhydride andthe hydroxyl functional groups, and avoid further esterification fromoccurring. Nonlimiting examples of suitable anhydrides includehexahydrophthalic anhydride, methyl hexahydrophthalic anhydride,phthalic anhydride, trimellitic anhydride, succinic anhydride,chlorendic anhydride, alkenyl succinic anhydride, and substitutedalkenyl anhydrides such as octenyl succinic anhydride, and mixtures ofany of the foregoing.

The half-ester group-containing reaction product thus prepared can befurther reacted with a monoepoxide to form a polysiloxane containingsecondary hydroxyl group(s). Nonlimiting examples of suitablemonoepoxides are phenyl glycidyl ether, n-butyl glycidyl ether, cresylglycidyl ether, isopropyl glycidyl ether, glycidyl versatate, forexample, CARDURA E available from Shell Chemical Co., and mixtures ofany of the foregoing.

In another embodiment of the present invention, the at least onepolysiloxane (A) is a carbamate functional group-containing polysiloxanewhich comprises the reaction product of at least the followingreactants:

-   -   (i) at least one polysiloxane containing silicon hydride of        structure (VI) above where R and n′ are as described above for        that structure;    -   (ii) at least one hydroxyl functional group-containing material        having one or more unsaturated bonds capable of undergoing        hydrosilylation reaction as described above; and    -   (iii) at least one low molecular weight carbamate functional        material, comprising the reaction product of an alcohol or        glycol ether and a urea.

Examples of such “low molecular weight carbamate functional material”include, but are not limited to, alkyl carbamate and hexyl carbamates,and glycol ether carbamates described in U.S. Pat. Nos. 5,922,475 and5,976,701, which is incorporated herein by reference.

The carbamate functional groups can be incorporated into thepolysiloxane by reacting the hydroxyl functional group-containingpolysiloxane with the low molecular weight carbamate functional materialvia a “transcarbamoylation” process. The low molecular weight carbamatefunctional material, which can be derived from an alcohol or glycolether, can react with free hydroxyl groups of a polysiloxane polyol,that is, material having an average of two or more hydroxyl groups permolecule, yielding a carbamate functional polysiloxane (A) and theoriginal alcohol or glycol ether. Reaction conditions and the ratio ofreactants (i), (ii) and (iii) are selected so as to form the desiredgroups.

The low molecular weight carbamate functional material can be preparedby reacting the alcohol or glycol ether with urea in the presence of acatalyst such as butyl stannoic acid. Nonlimiting examples of suitablealcohols include lower molecular weight aliphatic, cycloaliphatic andaromatic alcohols, for example, methanol, ethanol, propanol, butanol,cyclohexanol, 2-ethylhexanol, and 3-methylbutanol. Nonlimiting examplesof suitable glycol ethers include ethylene glycol methyl ether, andpropylene glycol methyl ether. The incorporation of carbamate functionalgroups into the polysiloxane also can be achieved by reacting isocyanicacid with free hydroxyl groups of the polysiloxane.

As aforementioned, in addition to or in lieu of hydroxyl or carbamatefunctional groups, the at least one polysiloxane (A) can contain one ormore other reactive functional groups such as carboxyl groups,isocyanate groups, blocked isocyanate groups, carboxylate groups,primary or secondary amine groups, amide groups, urea groups, urethanegroups, an anhydride group, a hydroxy alkylamide group, epoxy groups,and mixtures of any of the foregoing.

When the at least one polysiloxane (A) contains carboxyl functionalgroups, the at least one polysiloxane (A) can be prepared by reacting atleast one polysiloxane containing hydroxyl functional groups asdescribed above with a polycarboxylic acid or anhydride. Nonlimitingexamples of polycarboxylic acids suitable for use include adipic acid,succinic acid, and dodecanedioic acid. Nonlimiting examples of suitableanhydrides include those described above. Reaction conditions and theratio of reactants are selected so as to form the desired functionalgroups.

In the case where at least one polysiloxane (A) contains one or moreisocyanate functional groups, the at least one polysiloxane can beprepared by reacting at least one polysiloxane containing hydroxylfunctional groups, as described above, with a polyisocyanate, such as adiisocyanate. Nonlimiting examples of suitable polyisocyanates includealiphatic polyisocyanates, such as, for example, aliphaticdiisocyanates, for example, 1,4-tetramethylene diisocyanate and1,6-hexamethylene diisocyanate; cycloaliphatic polyisocyanates, forexample, 1,4-cyclohexyl diisocyanate, isophorone diisocyanate, andα,α-xylylene diisocyanate; and aromatic polyisocyanates, for example,4,4′-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, andtolylene diisocyanate. These and other suitable polyisocyanates aredescribed in more detail in U.S. Pat. No. 4,046,729, at column 5, line26 to column 6, line 28, incorporated herein by reference. Reactionconditions and the ratio of reactants are selected so as to form thedesired functional groups.

The substituent X in structure (IV) can comprise an oligomeric orpolymeric urethane or urea-containing material which is terminated withisocyanate, hydroxyl, primary or secondary amine functional groups, ormixtures of any of the foregoing. When the substituent X comprises suchfunctional groups, the at least one polysiloxane can be the reactionproduct of at least one polysiloxane polyol as described above, one ormore polyisocyanates and, optionally, one or more compounds having atleast two active hydrogen atoms per molecule selected from hydroxylgroups, primary amine groups, and secondary amine groups.

Nonlimiting examples of suitable polyisocyanates are those describedabove. Nonlimiting examples of compounds having at least two activehydrogen atoms per molecule include polyols and polyamines containingprimary or secondary amine groups.

Nonlimiting examples of suitable polyols include polyalkylene etherpolyols, including thio ethers; polyester polyols, including polyhydroxypolyesteramides; and hydroxyl-containing polycaprolactones andhydroxy-containing acrylic interpolymers. Also useful are polyetherpolyols formed from the oxyalkylation of various polyols, for example,glycols such as ethylene glycol, 1,6-hexanediol, Bisphenol A, and thelike, or higher polyols such as trimethylolpropane, pentaerythritol andthe like. Polyester polyols also can be used. These and other suitablepolyols are described in U.S. Pat. No. 4,046,729 at column 7, line 52 tocolumn 8, line 9; column 8, line 29 to column 9, line 66; and U.S. Pat.No. 3,919,315 at column 2, line 64 to column 3, line 33, bothincorporated herein by reference.

Nonlimiting examples of suitable polyamines include primary or secondarydiamines or polyamines in which the groups attached to the nitrogenatoms can be saturated or unsaturated, aliphatic, alicyclic, aromatic,aromatic-substituted-aliphatic, aliphatic-substituted-aromatic andheterocyclic. Exemplary suitable aliphatic and alicyclic diaminesinclude 1,2-ethylene diamine, 1,2-porphylene diamine, 1,8-octanediamine, isophorone diamine, propane-2,2-cyclohexyl amine, and the like.Suitable aromatic diamines include phenylene diamines and the toluenediamines, for example, o-phenylene diamine and p-tolylene diamine. Theseand other suitable polyamines are described in detail in U.S. Pat. No.4,046,729 at column 6, line 61 to column 7, line 26, incorporated hereinby reference.

In one embodiment, the substituent group X of the structure (IV) cancomprise a polymeric ester-containing group which is terminated withhydroxyl or carboxylic acid functional groups. When X is such a group,at least one polysiloxane can be the reaction product of one or morepolysiloxane polyols as described above, one or more materialscomprising at least one carboxylic acid functional group, and one ormore organic polyols. Nonlimiting suitable examples of materialscomprising at least one carboxylic acid functional group includecarboxylic acid group-containing polymers well-known in the art, forexample, carboxylic acid group-containing acrylic polymers, polyesterpolymers, and polyurethane polymers, such as those described in U.S.Pat. No. 4,681,811. Nonlimiting examples of suitable organic polyolsinclude those described above.

To form the at least one polysiloxane (A) containing epoxy groups, atleast one polysiloxane containing hydroxyl functional groups asdescribed above can be further reacted with a polyepoxide. Thepolyepoxide can be an aliphatic or cycloaliphatic polyepoxide ormixtures of any of the foregoing. Nonlimiting examples of polyepoxidessuitable for use include epoxy functional acrylic copolymers preparedfrom at least one ethylenically unsaturated monomer comprising at leastone epoxy group, for example glycidyl (meth)acrylate and allyl glycidylether, and one or more ethylenically unsaturated monomers which have noepoxy functionality. The preparation of such epoxy functional acryliccopolymers is described in detail in U.S. Pat. No. 4,681,811 at column4, line 52 to column 5, line 50, incorporated herein by reference.Reaction conditions and the ratio of reactants are selected so as toform the desired functional groups.

In the embodiment of the present invention where the boron-containingcompound is formed from the at least one functional group-containingpolysiloxane (A) and the boron-containing compound (B), the at least onepolysiloxane (A) can be reacted with the boron-containing compound (B)under condensation reaction conditions well known in the art. Forexample, mixing boric acid or a boric acid equivalent with a polyol andremoving water by distillation either directly or in combination with asolvent. Other methods for preparing boric acid esters can be found in“Kirk-Othmer Encyclopedia of Chemical Technology” 4th edition, Vol 4, p416; John Wiley and sons; 1992

Also, it should be understood, that the boron-containing compound can beformed in situ. That is, the composition from which one or both of thefirst and second polymeric layers is formed can comprise boric acidand/or a borate ester and an active hydrogen-containing component, suchas a polymer or polysiloxane comprising hydroxyl functional groups, asseparate components. The boron-containing compound can then be formed,for example, by forming the condensate reaction product, i.e., theborate ester, within the composition at ambient temperature or as thecomposition undergoes a curing reaction at elevated termperatures. Inthis instance, the composition can comprise the condensate reactionproduct, and the boric acid and/or the borate ester and the activehydrogen-containing component as three separate components.

In an alternative embodiment, the present invention providesthermosetting compositions, for example, curable coating compositionscomprising (A) at least one polymer comprising at least one reactivefunctional group, such as those described in detail below, (B) at leastone curing agent having at least one functional group reactive with thefunctional groups of (A), and (C) at least one compound selected from aborate, an aluminate, a titanate, a zirconate, a silicate, a siloxane, asilane and mixtures thereof, wherein each component is different.Typically, the at least one compound (C) is selected from at least oneof a borate and an aluminate.

Examples of suitable borates are those discussed above. Examples oftitanates suitable for use in the compositions of the present inventioninclude titanium isopropoxide, isopropyl triostearoyl titanate, dicyclo(dioct)pyrophosphato titanate, tetraisopropyl di(dioctyl)phosphito titanate. Suitable aluminates include aluminumalkoxides such as aluminum isoproxide, which is typically employed, andaluminum acetylacetonate. Exemplary of a suitable silicate is tetraethylorthosilicate. Suitable siloxanes include tetraisopropyldisiloxanes andtetramethylsiloxane. Suitable silanes include tetramethyl silyl ethers.In one embodiment of the present invention, a polysiloxane (a)comprising one or more hydroxyl functional groups is reacted with analuminum alkoxide such as aluminum triisopropoxide.

In the multi-layer composite of the present invention, the compound (C),which typically is selected from at least one of an aluminum alkoxide orboron-containing compound such as those described in detail above, ispresent in one or both of the first and second polymeric layers in anamount sufficient to improve the interlayer adhesion between the firstand the second polymeric layers. That is, when the compound (C) ispresent in one or both of the polymeric layers, the delamination oradhesion loss, as determined in accordance with ASTM-3359-97, method B,of the second polymeric layer from the first polymer layer can beincreased by one or more numerical units of the rating scale specifiedin the aforementioned method. As mentioned previously, one or both ofthe first polymeric layer and the second polymeric layer can be formedfrom a thermosetting composition. In one embodiment of the invention,one or both of the first polymeric layer and the second polymeric layercomprise a cured layer formed from a thermosetting compositioncomprising (A) at least one film-forming polymer having reactivefunctional groups; (B) at least one curing agent having functionalgroups reactive with the functional groups of (A); and (C) at least oneof the aforementioned boron-containing compounds, wherein the componentsare different.

When added to the other components that form the thermosettingcomposition from which the curable composition from which the firstand/or the second polymeric layer is formed, the adhesion promotercomposition, usually a boron-containing compound, (C) can be present inthe composition in an amount sufficient to provide an amount ofelemental adhesion promoter component (1), e.g., boron, present in thecomposition of at least 0.001 weight percent, often at least 0.025weight percent, usually at least 0.05 weight percent, and typically atleast 0.10 weight percent, based on total weight of the resin solidspresent in the composition. Also, the adhesion promoter composition,usually a boron-containing compound, (C), when added to the othercomponents that form the thermosetting composition from which thecurable composition from which the first and/or second polymeric layeris formed, can be present in the composition in an amount sufficient toprovide an amount of elemental adhesion promoting component (1), usuallyboron, present in the composition of less than 5 weight percent, oftenless than 3 weight percent, usually less than 2.5 weight percent, andtypically less than 2 weight percent, based on total weight of the resinsolids present in the composition. The amount of adhesion promotercomposition, e.g., boron-containing compound, (C) is present in thethermosetting composition in an amount sufficient to provide an amountof elemental adhesion promoting component (1), e.g., boron, present inthe composition that can range between any combination of these valuesinclusive of the recited values.

As aforementioned, the thermosetting composition of the presentinvention (which can comprise a curable coating composition, comprises,in addition to the compound (C), at least one film-forming polymercomprising at least one reactive functional group (A), and at least onereactant, typically a curing agent, (B) comprising at least onefunctional group which is reactive with the functional group of (A). Theat least one film-forming polymer having reactive functional groups (A)can be different from and in addition to the at least one curing agent(B), and compound (C). The film-forming polymer (A) can have at leastone functional group reactive with the curing agent (B), and, ifapplicable, the compound (C). In one embodiment, the at least onereactive functional group-containing film-forming polymer (A) can beselected from at least one of polyether polymers, polyester polymers,acrylic polymers, silicon- based polymers, polyepoxide polymers, andpolyurethane polymers.

In a particular embodiment of the present invention, the film-formingpolymer (A) can comprise at least one reactive functional group selectedfrom a hydroxyl group, a carboxyl group, an isocyanate group, a blockedisocyanate group, a primary amine group, a secondary amine group, anamide group, a carbamate group, a urea group, a urethane group, a vinylgroup, an unsaturated ester group, a maleimide group, a fumarate group,an anhydride group, a hydroxy alkylamide group, and an epoxy group.

In another embodiment of the present invention, the film-forming polymer(A) comprises at least one reactive functional group selected from ahydroxyl group, a carbamate group, an epoxy group, an isocyanate group,and a carboxyl group. In another embodiment, the polymer comprises atleast one reactive functional group selected from a hydroxyl group, anda carbamate group.

The film-forming polymer (A) can comprise a mixture of any of theforegoing reactive functional groups.

Film-forming polymers suitable for use as the at least one reactivefunctional group-containing film-forming polymer (A) can include any ofa variety of functional polymers known in the art. For example, suitablehydroxyl group-containing polymers can include acrylic polyols,polyester polyols, polyurethane polyols, polyether polyols, and mixturesthereof. In a particular embodiment of the present invention, thefilm-forming polymer is an acrylic polyol having a hydroxyl equivalentweight ranging from 1000 to 100 grams per solid equivalent, preferably500 to 150 grams per solid equivalent.

Suitable hydroxyl group and/or carboxyl group-containing acrylicpolymers can be prepared from polymerizable ethylenically unsaturatedmonomers and are typically copolymers of (meth)acrylic acid and/orhydroxylalkyl esters of (meth)acrylic acid with one or more otherpolymerizable ethylenically unsaturated monomers such as alkyl esters of(meth)acrylic acid including methyl (meth)acrylate, ethyl(meth)acrylate, butyl (meth)acrylate and 2-ethyl hexylacrylate, andvinyl aromatic compounds such as styrene, alpha-methyl styrene, andvinyl toluene. As used herein, “(meth)acrylate” and like terms isintended to include both acrylates and methacrylates.

In a one embodiment of the present invention the acrylic polymer can beprepared from ethylenically unsaturated, beta-hydroxy ester functionalmonomers. Such monomers can be derived from the reaction of anethylenically unsaturated acid functional monomer, such asmonocarboxylic acids, for example, acrylic acid, and an epoxy compoundwhich does not participate in the free radical initiated polymerizationwith the unsaturated acid monomer. Examples of such epoxy compoundsinclude glycidyl ethers and esters. Suitable glycidyl ethers includeglycidyl ethers of alcohols and phenols such as butyl glycidyl ether,octyl glycidyl ether, phenyl glycidyl ether and the like. Suitableglycidyl esters include those which are commercially available fromShell Chemical Company under the tradename CARDURA E; and from ExxonChemical Company under the tradename GLYDEXX-10. Alternatively, thebeta-hydroxy ester functional monomers can be prepared from anethylenically unsaturated, epoxy functional monomer, for exampleglycidyl (meth)acrylate and allyl glycidyl ether, and a saturatedcarboxylic acid, such as a saturated monocarboxylic acid, for exampleisostearic acid.

Epoxy functional groups can be incorporated into the polymer preparedfrom polymerizable ethylenically unsaturated monomers by copolymerizingoxirane group-containing monomers, for example glycidyl (meth)acrylateand allyl glycidyl ether, with other polymerizable ethylenicallyunsaturated monomers, such as those discussed above. Preparation of suchepoxy functional acrylic polymers is described in detail in U.S. Pat.No. 4,001,156 at columns 3 to 6, incorporated herein by reference.

Carbamate functional groups can be incorporated into the polymerprepared from polymerizable ethylenically unsaturated monomers bycopolymerizing, for example, the above-described ethylenicallyunsaturated monomers with a carbamate functional vinyl monomer such as acarbamate functional alkyl ester of methacrylic acid. Useful carbamatefunctional alkyl esters can be prepared by reacting, for example, ahydroxyalkyl carbamate, such as the reaction product of ammonia andethylene carbonate or propylene carbonate, with methacrylic anhydride.Other useful carbamate functional vinyl monomers include, for instance,the reaction product of hydroxyethyl methacrylate, isophoronediisocyanate, and hydroxypropyl carbamate; or the reaction product ofhydroxypropyl methacrylate, isophorone diisocyanate, and methanol. Stillother carbamate functional vinyl monomers may be used, such as thereaction product of isocyanic acid (HNCO) with a hydroxyl functionalacrylic or methacrylic monomer such as hydroxyethyl acrylate, and thosedescribed in U.S. Pat. No. 3,479,328, incorporated herein by reference.Carbamate functional groups can also be incorporated into the acrylicpolymer by reacting a hydroxyl functional acrylic polymer with a lowmolecular weight alkyl carbamate such as methyl carbamate. Pendantcarbamate groups can also be incorporated into the acrylic polymer by a“transcarbamoylation” reaction in which a hydroxyl functional acrylicpolymer is reacted with a low molecular weight carbamate derived from analcohol or a glycol ether. The carbamate groups exchange with thehydroxyl groups yielding the carbamate functional acrylic polymer andthe original alcohol or glycol ether. Also, hydroxyl functional acrylicpolymers can be reacted with isocyanic acid to provide pendent carbamategroups. Likewise, hydroxyl functional acrylic polymers can be reactedwith urea to provide pendent carbamate groups.

The polymers prepared from polymerizable ethylenically unsaturatedmonomers can be prepared by solution polymerization techniques, whichare well-known to those skilled in the art, in the presence of suitablecatalysts such as organic peroxides or azo compounds, for example,benzoyl peroxide or N,N-azobis(isobutylronitrile). The polymerizationcan be carried out in an organic solution in which the monomers aresoluble by techniques conventional in the art. Alternatively, thesepolymers can be prepared by aqueous emulsion or dispersionpolymerization techniques which are well-known in the art. The ratio ofreactants and reaction conditions are selected to result in an acrylicpolymer with the desired pendent functionality.

Polyester polymers are also useful in the coating compositions of theinvention as the film-forming polymer. Useful polyester polymerstypically include the condensation products of polyhydric alcohols andpolycarboxylic acids. Suitable polyhydric alcohols can include ethyleneglycol, neopentyl glycol, trimethylol propane, and pentaerythritol.Suitable polycarboxylic acids can include adipic acid, 1,4-cyclohexyldicarboxylic acid, and hexahydrophthalic acid. Besides thepolycarboxylic acids mentioned above, functional equivalents of theacids such as anhydrides where they exist or lower alkyl esters of theacids such as the methyl esters can be used. Also, small amounts ofmonocarboxylic acids such as stearic acid can be used. The ratio ofreactants and reaction conditions are selected to result in a polyesterpolymer with the desired pendent functionality, i.e., carboxyl orhydroxyl functionality.

For example, hydroxyl group-containing polyesters can be prepared byreacting an anhydride of a dicarboxylic acid such as hexahydrophthalicanhydride with a diol such as neopentyl glycol in a 1:2 molar ratio.Where it is desired to enhance air-drying, suitable drying oil fattyacids may be used and include those derived from linseed oil, soya beanoil, tall oil, dehydrated castor oil, or tung oil.

Carbamate functional polyesters can be prepared by first forming ahydroxyalkyl carbamate that can be reacted with the polyacids andpolyols used in forming the polyester. Alternatively, terminal carbamatefunctional groups can be incorporated into the polyester by reactingisocyanic acid with a hydroxy functional polyester. Also, carbamatefunctionality can be incorporated into the polyester by reacting ahydroxyl polyester with a urea. Additionally, carbamate groups can beincorporated into the polyester by a transcarbamoylation reaction.Preparation of suitable carbamate functional group-containing polyestersare those described in U.S. Pat. No. 5,593,733 at column 2, line 40 tocolumn 4, line 9, incorporated herein by reference.

Polyurethane polymers containing terminal isocyanate or hydroxyl groupsalso can be used as the polymer (d) in the coating compositions of theinvention. The polyurethane polyols or NCO-terminated polyurethaneswhich can be used are those prepared by reacting polyols includingpolymeric polyols with polyisocyanates. Polyureas containing terminalisocyanate or primary and/or secondary amine groups which also can beused are those prepared by reacting polyamines including polymericpolyamines with polyisocyanates. The hydroxyl/isocyanate oramine/isocyanate equivalent ratio is adjusted and reaction conditionsare selected to obtain the desired terminal groups. Examples of suitablepolyisocyanates include those described in U.S. Pat. No. 4,046,729 atcolumn 5, line 26 to column 6, line 28, incorporated herein byreference. Examples of suitable polyols include those described in U.S.Pat. No. 4,046,729 at column 7, line 52 to column 10, line 35,incorporated herein by reference. Examples of suitable polyaminesinclude those described in U.S. Pat. No. 4,046,729 at column 6, line 61to column 7, line 32 and in U.S. Pat. No. 3,799,854 at column 3, lines13 to 50, both incorporated herein by reference.

Carbamate functional groups can be introduced into the polyurethanepolymers by reacting a polyisocyanate with a polyester having hydroxylfunctionality and containing pendent carbamate groups. Alternatively,the polyurethane can be prepared by reacting a polyisocyanate with apolyester polyol and a hydroxyalkyl carbamate or isocyanic acid asseparate reactants. Examples of suitable polyisocyanates are aromaticisocyanates, such as 4,4′-diphenylmethane diisocyanate, 1,3-phenylenediisocyanate and toluene diisocyanate, and aliphatic polyisocyanates,such as 1,4-tetramethylene diisocyanate and 1,6-hexamethylenediisocyanate. Cycloaliphatic diisocyanates, such as 1,4-cyclohexyldiisocyanate and isophorone diisocyanate also can be employed.

Examples of suitable polyether polyols include polyalkylene etherpolyols such as those having the following structural formulas (VII) or(VIII):

wherein the substituent R is hydrogen or a lower alkyl group containingfrom 1 to 5 carbon atoms including mixed substituents, and n has a valuetypically ranging from 2 to 6 and m has a value ranging from 8 to 100 orhigher. Exemplary polyalkylene ether polyols includepoly(oxytetramethylene) glycols, poly(oxytetraethylene) glycols,poly(oxy-1,2-propylene) glycols, and poly(oxy-1,2-butylene) glycols.

Also useful are polyether polyols formed from oxyalkylation of variouspolyols, for example, glycols such as ethylene glycol, 1,6-hexanediol,Bisphenol A, and the like, or other higher polyols such astrimethylolpropane, pentaerythritol, and the like. Polyols of higherfunctionality which can be utilized as indicated can be made, forinstance, by oxyalkylation of compounds such as sucrose or sorbitol. Onecommonly utilized oxyalkylation method is reaction of a polyol with analkylene oxide, for example, propylene or ethylene oxide, in thepresence of an acidic or basic catalyst. Specific examples of polyethersinclude those sold under the names TERATHANE and TERACOL, available fromE. I. Du Pont de Nemours and Company, Inc.

Generally, the polymers having reactive functional groups which areuseful in the coating compositions of the invention have a weightaverage molecular weight (Mw) typically ranging from 1000 to 20,000preferably 1500 to 15,000 and more preferably 2000 to 12,000 asdetermined by gel permeation chromatography using a polystyrenestandard.

Hydroxyl and/or carbamate functional group-containing polymers aretypically employed.

Polyepoxides such as those described below with reference to the curingagent (B), can also be used.

The polymer having reactive functional groups (A) can be present in thethermosetting compositions in an amount of at least 2 percent by weight,usually at least 5 percent by weight, and typically at least 10 percentby weight based on weight of total resin solids in the coatingcomposition. Also, the polymer having reactive functional groups can bepresent in the thermosetting compositions of the invention in an amountless than 80 percent by weight, usually less than 60 percent by weight,and typically less than 50 percent by weight based on weight of totalresin solids in the coating composition. The amount of the polymer (A)having reactive functional groups present in the thermosettingcompositions of the present invention can range between any combinationof these values inclusive of the recited values.

As aforementioned, in addition to the functional group-containingfilm-forming polymer (A) and the boron-containing compound (C), thethermosetting composition of the present invention further comprises atleast one curing agent having functional groups reactive with thefunctional groups of the film-forming polymer (A) (and/or the adhesionpromoter composition, e.g. boron containing compound (C), whereapplicable).

Dependent upon the reactive functional groups of the film-formingpolymer (A)(and, optionally, the composition/compound (C)), this curingagent can be selected from an aminoplast resin, a polyisocyanate, ablocked isocyanate, a polyepoxide, a polyacid, an anhydride, an amine, apolyol, and mixtures of any of the foregoing. In one embodiment, the atleast one curing agent (B) is selected from an aminoplast resin and apolyisocyanate.

In another embodiment, the present invention is directed to anycomposition as previously described wherein the curing agent comprisesan aminoplast resin. Aminoplast resins, which can comprise phenoplasts,as curing agents for hydroxyl, carboxylic acid, and carbamate functionalgroup-containing materials are well known in the art. Suitableaminoplast resins, such as, for example, those discussed above, areknown to those of ordinary skill in the art. Aminoplasts can be obtainedfrom the condensation reaction of formaldehyde with an amine or amide.Nonlimiting examples of amines or amides include melamine, urea, orbenzoguanamine. Condensates with other amines or amides can be used; forexample, aldehyde condensates of glycoluril, which give a high meltingcrystalline product useful in powder coatings. While the aldehyde usedis most often formaldehyde, other aldehydes such as acetaldehyde,crotonaldehyde, and benzaldehyde can be used.

The aminoplast resin contains imino and methylol groups and in certaininstances at least a portion of the methylol groups are etherified withan alcohol to modify the cure response. Any monohydric alcohol can beemployed for this purpose including methanol, ethanol, n-butyl alcohol,isobutanol, and hexanol.

Nonlimiting examples of aminoplasts include melamine-, urea-, orbenzoguanamine-formaldehyde condensates, in certain instances monomericand at least partially etherified with one or more alcohols containingfrom one to four carbon atoms. Nonlimiting examples of suitableaminoplast resins are commercially available, for example, from CytecIndustries, Inc. under the trademark CYMEL® and from Solutia, Inc. underthe trademark RESIMENE®.

In another embodiment of the present invention, the curing agentcomprises an aminoplast resin which, when added to the other componentsthat form the thermosetting composition, is generally present in anamount ranging from 2 weight percent to 65 weight percent, can bepresent in an amount ranging from 5 weight percent to 50 weight percent,and typically is present in an amount ranging from 5 weight percent to40 weight percent based on total weight of resin solids present in thecomposition.

In yet another embodiment of the present invention, the at least onereactant (B) comprises a polyisocyanate curing agent. As used herein,the term “polyisocyanate” is intended to include blocked (or capped)isocyanates as well as unblocked (poly)isocyanates. The polyisocyanatecan be an aliphatic or an aromatic polyisocyanate, or a mixture of theforegoing two. Diisocyanates can be used, although higherpolyisocyanates such as isocyanurates of diisocyanates are often used.Higher polyisocyanates also can be used in combination withdiisocyanates. Isocyanate prepolymers, for example, reaction products ofpolyisocyanates with polyols also can be used. Mixtures ofpolyisocyanate curing agents can be used.

If the polyisocyanate is blocked or capped, any suitable aliphatic,cycloaliphatic, or aromatic alkyl monoalcohol known to those skilled inthe art can be used as a capping agent for the polyisocyanate. Othersuitable capping agents include oximes and lactams. When used, thepolyisocyanate curing agent is typically present, when added to theother components which form the coating composition, in an amountranging from 5 to 65 weight percent, can be present in an amount rangingfrom 10 to 45 weight percent, and often are present in an amount rangingfrom 15 to 40 percent by weight based on the total weight of resinsolids present in the composition.

Other useful curing agents comprise blocked isocyanate compounds suchas, for example, the tricarbamoyl triazine compounds described in detailin U.S. Pat. No. 5,084,541, which is incorporated by reference herein.When used, the blocked polyisocyante curing agent can be present, whenadded to the other components in the composition, in an amount rangingup to 20 weight percent, and can be present in an amount ranging from 1to 20 weight percent, based on the total weight of resin solids presentin the composition.

In one embodiment of the present invention, the curing agent comprisesboth an aminoplast resin and a polyisocyanate.

Anhydrides as curing agents for hydroxyl functional group-containingmaterials also are well known in the art and can be used in the presentinvention. Nonlimiting examples of anhydrides suitable for use as curingagents in the compositions of the invention include those having atleast two carboxylic acid anhydride groups per molecule which arederived from a mixture of monomers comprising an ethylenicallyunsaturated carboxylic acid anhydride and at least one vinyl co-monomer,for example, styrene, alpha- methyl styrene, vinyl toluene, and thelike. Nonlimiting examples of suitable ethylenically unsaturatedcarboxylic acid anhydrides include maleic anhydride, citraconicanhydride, and itaconic anhydride. Alternatively, the anhydride can bean anhydride adduct of a diene polymer such as maleinized polybutadieneor a maleinized copolymer of butadiene, for example, a butadiene/styrenecopolymer. These and other suitable anhydride curing agents aredescribed in U.S. Pat. No. 4,798,746 at column 10, lines 16-50; and inU.S. Pat. No. 4,732,790 at column 3, lines 41-57, both of which areincorporated herein by reference.

Polyepoxides as curing agents for carboxylic acid functionalgroup-containing materials are well known in the art. Nonlimitingexamples of polyepoxides suitable for use in the compositions of thepresent invention comprise polyglycidyl esters (such as acrylics fromglycidyl methacrylate), polyglycidyl ethers of polyhydric phenols and ofaliphatic alcohols, which can be prepared by etherification of thepolyhydric phenol, or aliphatic alcohol with an epihalohydrin such asepichlorohydrin in the presence of alkali. These and other suitablepolyepoxides are described in U.S. Pat. No. 4,681,811 at column 5, lines33 to 58, which is incorporated herein by reference.

Suitable curing agents for epoxy functional group-containing materialscomprise polyacid curing agents, such as the acid group-containingacrylic polymers prepared from an ethylenically unsaturated monomercontaining at least one carboxylic acid group and at least oneethylenically unsaturated monomer which is free from carboxylic acidgroups. Such acid functional acrylic polymers can have an acid numberranging from 30 to 150. Acid functional group-containing polyesters canbe used as well. The above-described polyacid curing agents aredescribed in further detail in U.S. Pat. No. 4,681,811 at column 6, line45 to column 9, line 54, which is incorporated herein by reference.

Also well known in the art as curing agents for isocyanate functionalgroup-containing materials are polyols, that is, materials having two ormore hydroxyl groups per molecule, different from component (b) whencomponent (b) is a polyol. Nonlimiting examples of such materialssuitable for use in the compositions of the invention includepolyalkylene ether polyols, including thio ethers; polyester polyols,including polyhydroxy polyesteramides; and hydroxyl-containingpolycaprolactones and hydroxy-containing acrylic copolymers. Also usefulare polyether polyols formed from the oxyalkylation of various polyols,for example, glycols such as ethylene glycol, 1,6-hexanediol, BisphenolA and the like, or higher polyols such as trimethylolpropane,pentaerythritol, and the like. Polyester polyols also can be used. Theseand other suitable polyol curing agents are described in U.S. Pat. No.4,046,729 at column 7, line 52 to column 8, line 9; column 8, line 29 tocolumn 9, line 66; and U.S. Pat. No. 3,919,315 at column 2, line 64 tocolumn 3, line 33, both of which are incorporated herein by reference.

Polyamines also can be used as curing agents for isocyanate functionalgroup-containing materials. Nonlimiting examples of suitable polyaminecuring agents include primary or secondary diamines or polyamines inwhich the radicals attached to the nitrogen atoms can be saturated orunsaturated, aliphatic, alicyclic, aromatic,aromatic-substituted-aliphatic, aliphatic-substituted-aromatic, andheterocyclic. Nonlimiting examples of suitable aliphatic and alicyclicdiamines include 1,2-ethylene diamine, 1,2-porphylene diamine,1,8-octane diamine, isophorone diamine, propane-2,2-cyclohexyl amine,and the like. Nonlimiting examples of suitable aromatic diamines includephenylene diamines and the toluene diamines, for example, o-phenylenediamine and p-tolylene diamine. These and other suitable polyaminesdescribed in detail in U.S. Pat. No. 4,046,729 at column 6, line 61 tocolumn 7, line 26, which is incorporated herein by reference.

When desired, appropriate mixtures of curing agents may be used. Itshould be mentioned that the thermosetting compositions compositions canbe formulated as a one-component composition where a curing agent suchas an aminoplast resin and/or a blocked isocyanate compound such asthose described above is admixed with other composition components. Theone-component composition can be storage stable as formulated.Alternatively, compositions can be formulated as a two-componentcomposition where a polyisocyanate curing agent such as those describedabove can be added to a pre-formed admixture of the other compositioncomponents just prior to application. The pre-formed admixture cancomprise curing agents such as aminoplast resins and/or blockedisocyanate compounds such as those described above.

In another embodiment in which the thermoseting composition can form acoating which is cured by actinic radiation or the combination ofactinic radiation and thermal energy, the components from which thecoating composition are formed further can comprise at least onephotoinitiator or photosensitizer which provides free radicals orcations to initiate the polymerization process. Useful photoinitiatorshave an adsorption in the range of 150 to 2,000 nm. Non-limitingexamples of useful photoinitiators include benzoin, benzophenone,hydroxy benzophenone, anthraquinone, thioxanthone, substituted benzoinssuch as butyl isomers of benzoin ethers, α,α-diethoxyacetophenone,α,α-dimethoxy-α-phenylacetophenone, 2-hydroxy-2-methyl-1-phenyl propane1-one and 2,4,6-trimethyl benzoyl diphenyl phosphine oxide.

In one embodiment, the present invention is directed to an improvedcurable coating composition used to form a multi-layer composite coatingcomprising at least a first coating layer formed on at least a portionof a substrate, and a second coating layer formed over at least aportion of the first coating layer, where one or both the first coatinglayer and the second coating layer are formed from the curable coatingcomposition, and wherein in the absence of a boron-containing compound,the first and second coating layers. have poor interlayer adhesion. Theimprovement comprises the inclusion in the curable coating compositionof a boron-containing compound present in an amount sufficient toimprove the interlayer adhesion between the first coating layer and thesecond coating layer.

The curable coating composition of the present invention can compriseany of the foregoing thermosetting compositions described above. Also,in the multi-layer composite coating wherein both of the first andsecond coating layers are formed from the curable composition, it shouldbe understood that each of the first and second coating layers can beformed from the same or different curable coating compositions.

In a particular embodiment, the present invention is directed to amulti-layer composite coating as discussed above where one or both ofthe first coating layer and the second coating layer are formed from acurable coating composition formed from components comprising (A) anacrylic and/or a polyester polymer having at least one reactivefunctional group selected from a hydroxyl group, a carbamate group, andmixtures thereof; such as any of those described above, (B) a curingagent selected from an aminoplast resin and a polyisocyanate, such asthose described above, and (C) any of the foregoing adhesion promotercompositions, e.g., boron-containing compounds, described above. Inanother embodiment, the present invention is directed to a multi-layercomposite coating as discussed above where one or both of the firstcoating layer and the second coating layer are formed from a curablecoating composition formed from components comprising (A) an acrylicand/or a polyester polymer having at least one reactive functional groupselected from a hydroxyl group, a carbamate group, and mixtures thereof;(B) a curing agent selected from an aminoplast resin and a blockedisocyanate compound comprising a tricarbamoyl triazine; and (C) any ofthe boron-containing compounds described above.

The curable coating compositions of the present invention can besolvent-based compositions, water-based compositions, in solidparticulate form, that is, a powder composition, in the form of a powderslurry or an aqueous dispersion. The components of the present inventionused to form the compositions of the present invention can be dissolvedor dispersed in an organic solvent. Nonlimiting examples of suitableorganic solvents include alcohols, such as butanol; ketones, such asmethyl amyl ketone; aromatic hydrocarbons, such as xylene; and glycolethers, such as, ethylene glycol monobutyl ether; esters; othersolvents; and mixtures of any of the foregoing.

In solvent based compositions, the organic solvent is generally presentin amounts ranging from 5 to 80 percent by weight based on total weightof the resin solids of the components which form the composition, andcan be present in an amount ranging from 30 to 50 percent by weight. Thecompositions as described above can have a total solids content rangingfrom 40 to 75 percent by weight based on total weight of the resinsolids of the components which form the composition, and can have atotal solids content ranging from 50 to 70 percent by weight.Alternatively, the inventive compositions can be in solid particulateform suitable for use as a powder coating, or suitable for dispersion ina liquid medium such as water for use as a powder slurry.

In a further embodiment, the compositions as previously describedfurther comprise a catalyst which is present during the composition'sformation. In one embodiment, the catalyst is present in an amountsufficient to accelerate the reaction between at least one reactivefunctional group of the at least one curing agent and/or at least onereactive functional group of the at least one film-forming polymer.

Nonlimiting examples of suitable catalysts include acidic materials, forexample, acid phosphates, such as phenyl acid phosphate, and substitutedor unsubstituted sulfonic acids such as dodecylbenzene sulfonic acid orpara-toluene sulfonic acid. Non-limiting examples of suitable catalystsfor reactions between isocyanate groups and active hydrogen-containingmaterials, for example, those comprising hydroxyl groups, include tincatalysts such as dibutyl tin dilaurate and dibutyl tin oxide.Non-limiting examples of epoxy acid base catalysts include tertiaryamines such as N,N′-dimethyldodecyl amine catalysts. In anotherembodiment, the catalyst can be a phosphatized polyester or aphosphatized epoxy. In this embodiment, the catalyst can be, forexample, the reaction product of phosphoric acid and a bisphenol Adiglycidyl ether having two hydrogenated phenolic rings, such asDRH-151, which is commercially available from Shell Chemical Co. Thecatalyst can be present, when added to the other components that formthe composition, in an amount ranging from 0.1 to 5.0 percent by weight,and is typically present in an amount ranging from 0.5 to 1.5 percent byweight based on the total weight of resin solids present in thecomposition.

In another embodiment, additional components can be present during theformation of the compositions as previously described. These additionalcomponents include, but are not limited to, particles different fromcomponents (A), (B) and (C), for example, silica in colloidal, fumed, oramorphous form, alumina or colloidal alumina, titanium dioxide, cesiumoxide, yttrium oxide, colloidal yttria, zirconia, e.g., colloidal oramorphous zirconia, and mixtures of any of the foregoing, flexibilizers,plasticizers, surface active agents, thixotropic agents, rheologycontrol modifiers, anti-gassing agents, organic cosolvents, flowcontrollers, hindered amine light stabilizers, anti- oxidants, UV lightabsorbers, coloring agents or tints, and similar additives conventionalin the art, as well as mixtures of any of the foregoing can be includedin the composition. These additional ingredients can be present, whenadded to the other components that form the composition, in an amount upto 40 percent by weight based on the total weight of resin solidspresent in the composition.

In one embodiment, the present invention is directed to a multi-layercomposite coating wherein the first curable coating compositioncomprises a base coating composition and the second curable compositioncomprises a top coating composition. In another embodiment of thepresent invention, the base coating composition comprises asubstantially pigment-free coating composition and the top coatingcomposition comprises a substantially pigment-free top coatingcomposition. In an alternative embodiment of the present invention, thebase coating composition comprises a pigment-containing coatingcomposition and the top coating composition comprises apigment-containing composition. In another embodiment of the presentinvention, the base coating composition comprises a pigment-containingcoating composition and the top coating composition comprises asubstantially pigment-free coating composition. In another embodiment ofthe present invention, the base coating composition comprises asubstantially pigment-free base coating:composition and the top coatingcomposition comprises a pigment-containing coating composition.

As used herein, by “substantially pigment-free coating composition” ismeant a coating composition which forms a transparent coating, such as aclearcoat in a multi-component composite coating composition. Suchcompositions are sufficiently free of pigment or particles such that theoptical properties of the resultant coatings are not seriouslycompromised. As used herein, “transparent” means that the cured coatinghas a BYK Haze index of less than 50 as measured using a BYK/Haze Glossinstrument.

The pigment-containing coating compositions can be any of the pigmentedcompositions commonly used in the coatings industry. For example, thepigment-containing coating composition can comprise a primer coatingcomposition, such as a pigmented thermosetting weldable primer coatingcomposition, for example, those commercially available under thetradename BONAZINC®, an electrodepositable coating composition such asED-5000, a primer-surfacer coating composition such as GPX45379, acolor-enhancing base coat such as HWB-9517, and ODCT-6373, all availablefrom PPG Industries, Inc. of Pittsburgh, Penn., or an adhesivecomposition such as those used as automotive windshield adhesives, forexample BETASEAL 15625 available from Essex Specialty Products.

Likewise, the pigment-free curable coating composition can comprise anyof the pigment-free coatings known in the art such as those used asclear coats in color-plus-clear coating systems for the automotiveindustry. Non-limiting examples include TKU1050AR, ODCT-8000, and thoseavailable under the tradename DIAMONDCOAT® and NCT®, all commerciallyavailable from PPG Industries, Inc.

In another embodiment, the present invention is directed tomulti-component composite coating compositions comprising a basecoatdeposited from a pigment-containing base coating composition, which cancomprise any of the aforementioned curable coating compositions, and atopcoat deposited from any of the coating compositions of the presentinvention previously described above. In one embodiment, the presentinvention is directed to a multi-component composite coating compositionas previously described, wherein the topcoating composition istransparent after curing and is selected from any of the compositionspreviously described. The components used to form the topcoatingcomposition in these embodiments can be selected from the coatingcomponents discussed above, and additional components also can beselected from those recited above. It should be understood that one orboth of the basecoating composition and the top coating composition canbe formed from the curable coating compositions of the presentinvention.

The basecoat and transparent topcoat (i.e., clearcoat) compositions usedin the multi-component composite coating compositions of the presentinvention in certain instances can be formulated into liquid high solidscoating compositions, that is, compositions containing 40 percent, orgreater than 50 percent by weight resin solids. The solids content canbe determined by heating a sample of the composition to 105° C. to 110°C. for 1-2 hours to drive off the volatile material, and subsequentlymeasuring relative weight loss. As aforementioned, although thecompositions can be liquid coating compositions, they also can beformulated as powder coating compositions.

Where the basecoat is not formed from a composition of the presentinvention (but the topcoat is formed from a curable coating compositionof the present invention) the coating composition of the basecoat in thecolor-plus-clear system can be any of the compositions useful incoatings applications, particularly automotive applications. The coatingcomposition of the basecoat can comprise a resinous binder and a pigmentto act as the colorant. Nonlimiting examples of resinous binders areacrylic polymers, polyesters, alkyds, and polyurethanes.

The resinous binders for the basecoat can be organic solvent-basedmaterials such as those described in U.S. Pat. No. 4,220,679, notecolumn 2, line 24 continuing through column 4, line 40, which portionsare incorporated by reference. Also, water-based coating compositionssuch as those described in U.S. Pat. Nos. 4,403,003, 4,147,679 and5,071,904 can be used as the binder in the basecoat composition. TheseU.S. patents are incorporated herein by reference.

The basecoat composition can comprise one or more pigments as colorants.Nonlimiting examples of suitable metallic pigments include aluminumflake, copper bronze flake, and metal oxide coated mica.

Besides the metallic pigments, the basecoat compositions can containnonmetallic color pigments conventionally used in surface coatings suchas, for example, inorganic pigments such as titanium dioxide, ironoxide, chromium oxide, lead chromate, and carbon black; and organicpigments such as phthalocyanine blue and phthalocyanine green.

Optional ingredients in the basecoat composition can comprise thosewhich are well known in the art of formulating surface coatings and cancomprise surface active agents, flow control agents, thixotropic agents,fillers, anti-gassing agents, organic co-solvents, catalysts, and othercustomary auxiliaries. Nonlimiting examples of these materials andsuitable amounts are described in U.S. Pat. Nos. 4,220,679; 4,403,003;4,147,769; and 5,071,904, which patents are incorporated herein byreference.

The basecoat compositions can be applied to the substrate by anyconventional coating technique such as brushing, spraying, dipping, orflowing. Spray techniques and equipment for air spraying, airless spray,and electrostatic spraying in either manual or automatic methods, knownin the art can be used.

During application of the basecoat to the substrate, the film thicknessof the basecoat formed on the substrate can range from 0.1 to 5 mils. Inanother embodiment, the film thickness of the basecoat formed on thesubstrate can range 0.1 to 1 mils, and can be 0.4 mils.

After forming a film of the basecoat on the substrate, the basecoat canbe cured or alternatively given a drying step in which solvent is drivenout of the basecoat film by heating or an air drying period beforeapplication of the clearcoat. Suitable drying conditions may depend onthe particular basecoat composition, and on the ambient humidity if thecomposition is water-borne, but a drying time from 1 to 15 minutes at atemperature of 75° to 200° F. (210 to 93° C.) can be adequate.

The transparent or clear topcoat composition can be applied to thebasecoat by any conventional coating technique, including, but notlimited to, compressed air spraying, electrostatic spraying, and eithermanual or automatic methods. The transparent topcoat can be applied to acured or to a dried basecoat before the basecoat has been cured. In thelatter instance, the two coatings can then be heated to cure bothcoating layers simultaneously. Typical curing conditions can range from50° F. to 475° F. (10° C. to 246° F.) for 1 to 30 minutes. Theclearcoating thickness (dry film thickness) can be 1 to 6 mils.

A second topcoat coating composition can be applied to the first topcoatto form a “clear-on-clear” topcoat. The first topcoat coatingcomposition can be applied over the basecoat as described above. Thesecond topcoat coating composition can be applied to a cured or to adried first topcoat before the basecoat and first topcoat have beencured. The basecoat, the first topcoat and the second topcoat can thenbe heated to cure the three coatings simultaneously.

It should be understood that the second transparent topcoat and thefirst transparent topcoat coating compositions can be the same ordifferent provided that, when applied wet-on-wet, one topcoat does notsubstantially interfere with the curing of the other for example byinhibiting solvent/water evaporation from a lower layer. Moreover, thefirst topcoat, the second topcoat or both can be the curable coatingcomposition of the present invention. Alternatively, only one of thefirst topcoat and the second topcoat is formed from the curable coatingcomposition of the present invention.

In this instance, the topcoat that does not comprise the curable coatingcomposition of the present invention can include any of thecrosslinkable coating compositions comprising at least onethermosettable coating material and at least one curing agent. Suitablewaterborne clearcoats for this purpose are disclosed in U.S. Pat. No.5,098,947 (incorporated by reference herein) and are based onwater-soluble acrylic resins. Useful solvent borne clearcoats aredisclosed in U.S. Pat. Nos. 5,196,485 and 5,814,410 (incorporated byreference herein) and include polyepoxides and polyacid curing agents.Suitable powder clearcoats for this purpose are described in U.S. Pat.No. 5,663,240 (incorporated by reference herein) and include epoxyfunctional acrylic copolymers and polycarboxylic acid curing agents.

Typically, after forming the first topcoat over the basecoat, the firsttopcoat is given a drying step in which solvent is driven out of thefilm by heating or, alternatively, an air drying period or curing stepbefore application of the second topcoat. Suitable drying conditionswill depend on the particular first topcoat composition, and on theambient humidity if the composition is water-borne, but, in general, adrying time from 1 to 15 minutes at a temperature of 75° F. to 200° F.(21° C. to 93° C.) will be adequate.

The film-forming composition of the present invention when employed as asecond topcoat coating composition can be applied as described above forthe first topcoat by any conventional coating application technique.Curing conditions can be those described above for the topcoat. Thesecond topcoating dry film thickness can range from 0.1 to 3 mils (7.5micrometers to 75 micrometers).

It should be mentioned that the coating compositions of the presentinvention can be advantageously formulated as a “monocoat”, that is acoating which forms essentially one coating layer when applied to asubstrate. The monocoat coating composition can be pigmented.Nonlimiting examples of suitable pigments include those mentioned above.When employed as a monocoat, the coating compositions of the presentinvention can be applied (by any of the conventional applicationtechniques discussed above) in two or more successive coats, and, incertain instances can be applied with only an ambient flash periodbetween coats. The multi-coats when cured can form essentially onecoating layer.

In one embodiment, the present invention is directed to a method ofrepairing a multi-layer composite coating comprising a base coat formedon a substrate from a film-forming base coating composition and a firsttop coat deposited over at least a portion of the base coat, the firsttop coat formed from a first film-forming top coating compositioncomprising any of the foregoing coating compositions, the methodcomprising locating an area of the composite coating which is flawed,and applying a repair top coat film-forming composition to the flawedarea after the flawed area has been prepared for repairing. The repairtopcoat film-forming composition can comprise a film-forming compositionwhich is the same or different from the first topcoat film-formingcomposition. The flawed area can be any coating blemish that cannot bepolished out, for example dirt particles in the coating surface. Theflawed area typically can be abraded or sanded to remove such coatingblemishes. In a repair carried out in accordance with the method of thepresent invention, the first top coating can provide excellent intercoatadhesion with the subsequently applied repair top coating.

The coating compositions of the present invention can provide curedcoatings having excellent intercoat or interlayer adhesion tosubsequently applied coating layers. For example, any of theaforementioned substantially pigment-free coating compositions can beapplied as a transparent clearcoat in a color-plus-clear coating systemas discussed above. In the event of damage to the cured coating systemcausing a surface defect, it may be necessary to prepare the damagedarea for repair with a subsequently applied clear coat composition. Thecoating compositions of the present invention can provide excellentintercoat adhesion between the first clear coat layer and thesubsequently applied repair clear coat layer. Likewise, when used as atop coat composition, the coating compositions of the present inventionalso provide excellent interlayer adhesion between the cured top coatand a subsequently applied windshield adhesive without the interveningstep of applying an adhesion promoting primer.

Illustrating the invention are the following examples that are not to beconsidered as limiting the invention to their details. All parts andpercentages in the examples, as well as throughout the specification,are by weight unless otherwise indicated.

EXAMPLES

Example AA describes the preparation of a polysiloxane polyol. ExamplesBB and CC describe the preparation of a carbamate functional acrylicresin and a carbamate functional polyester resin, respectively. ExamplesA through J describe the preparation of various adhesion promoters usedin the compositions of the present invention. Coating compositionExamples 1 through 9 describe the preparation of one-componentclearcoating compositions. Examples 10 through 13 describe thepreparation of clearcoating compositions based on epoxy-containingacrylic resins in conjunction with acid functional curing agents.Examples 14 through 23 describe the preparation of two-componentclearcoating compositions. Examples 24 and 25 describe the preparationof basecoating compositions. Examples 26 through 30 describe thepreparation of clearcoating compositions based on carbamategroup-containing resins, and Examples 31 through 33 describe thepreparation of powder clearcoating compositions.

Resin Compositions Example AA Polysiloxane Polyol

This example describes the preparation of a polysiloxane polyol whichwas subsequently used to form respective silica dispersions of ExamplesA and B, and the adhesion promoters used in the thermosettingcompositions of the present invention. The polysiloxane polyol was aproduct of the hydrosilylation of a reactive silicone fluid having anapproximate degree of polymerization of 3 to 7, i.e., (Si—O)₃ to(Si—O)₇. The polysiloxane polyol was prepared from a proportionatelyscaled-up batch of the following mixture of ingredients in the ratiosindicated: Equivalent Parts By Weight Ingredients Weight Equivalents(kilograms) Charge I: Trimethylolpropane 174.0 756.0 131.54 monoallylether Charge II: MASILWAX BASE¹  156.7² 594.8 93.21 Charge III:Chloroplatinic acid 10 ppm Toluene 0.23 Isopropanol 0.07¹Polysiloxane-containing silicon hydride, commercially available fromBASF Corporation.²Equivalent weight based on mercuric bichloride determination.

To a suitable reaction vessel equipped with a means for maintaining anitrogen blanket, Charge I and an amount of sodium acetate equivalent to20 to 25 ppm of total monomer solids was added at ambient conditions andthe temperature was gradually increased to 75° C. under a nitrogenblanket. At that temperature, about 5.0% of Charge II was added underagitation, followed by the addition of Charge III, equivalent to 10 ppmof active platinum based on total monomer solids. The reaction was thenallowed to exotherm to 95° C. at which time the remainder of Charge IIwas added at a rate such that the temperature did not exceed 95° C.After completion of this addition, the reaction temperature wasmaintained at 95° C. and monitored by infrared spectroscopy fordisappearance of the silicon hydride absorption band (Si—H, 2150 cm⁻¹).

Example BB Carbamate Functionalacrylic Polymer

This example describes the preparation of a carbamate functional acrylicused in the clearcoating compositions of Examples 26-30 described below.The polymer was prepared from the following ingredients: IngredientWeight in Parts Acrylic polymer¹ 1614.4 Methyl carbamate 240.3 Butylstannoic acid 3.05 Triphenyl phosphite 3.05¹Prepared from hydroxypropyl acrylate, butyl methacrylate and alphamethyl styrene dimer, 90% solids in DOWANOL ® PM.

A suitable reactor equipped with a thermocouple, overhead stirrer,nitrogen inlet and a reflux condenser was charged with the aboveingredients. The reaction mixture was heated to a temperature of 145° C.under a nitrogen blanket. At this temperature, reflux was observed. Thereaction mixture was held at reflux for one hour. After the hold periodwas complete, the reflux condenser was removed, and the reactor equippedfor distillation (short column, still head, thermocouple, and receiver)at atmospheric pressure. Distillate began to come over at 139° C. Thetemperature of the reaction was gradually raised to 151° C. to maintaina steady rate of distillation. At this point, 87 parts of distillate hadbeen collected. The reaction mixture was then cooled to 140° C. andequipped for simple vacuum distillation (still head, vacuum adapter,receiver flask). Distillation was resumed under reduced pressure; thepressure inside the reactor was gradually reduced to maintaindistillation until a reactor pressure of 60-mm Hg was attained. When thedistillation was essentially stopped, the reaction mixture was sampledand the hydroxyl value found to be 36. The additional distillatecollected totaled 158 parts. The contents of the reactor were thendiluted with 410 parts of ethyl 3-ethoxypropionate and 410 parts DOWANOLPM. The final resin solution was found to have solids content of 64.5%,determined at 110° C. for one hour. The weight average molecular weightwas about 10,400 and the number average molecular weight was about2,900, as determined by gel permeation chromatography using apolystyrene standard.

Example CC Carbamate Functional Polyester

This example describes the preparation of a carbamate-functionalpolyester resin used in the carbamate containing clearcoatingcompositions of the present invention. The carbamate functionalpolyester resin was prepared from the following ingredients: IngredientWeight in Parts Polyester¹ 6916.4 Methyl carbamate 1081.4 Butyl stannoicacid 14.4 Triphenyl phosphite 14.4 DOWANOL PM 1297.7¹Polyester polymer prepared from2,2,4-trimethyl-1,3-pentanediol/trimethylol propane/neopentyl# glycol/hexahydrophthalic anhydride in a 22.7:10.6:17.5:49.2 weightratio, 100% solids.

A suitable reactor was charged with the above ingredients and equippedwith a thermocouple, overhead stirrer, nitrogen inlet and a refluxcondenser. The mixture was heated to a temperature of 141° C. under anitrogen blanket. At this temperature reflux was observed. The reactionmixture was held at reflux for one hour. After the hold period wascomplete, the reflux condenser was removed, and the reactor equipped fordistillation (short column, still head, thermocouple, and receiver) atatmospheric pressure. Distillate began to come over at 132° C. Thetemperature of the reaction was gradually raised to 151° C. to maintaina steady rate of distillation. At this point 422 parts of distillate hadbeen collected. The reaction mixture was then cooled to 145° C. andequipped for simple vacuum distillation (still head, vacuum adapter,receiver flask). Distillation was resumed under reduced pressure; thepressure inside the reactor was gradually reduced to maintaindistillation until a reactor pressure of 60-mm Hg was attained. When thedistillation was essentially stopped, the reaction mixture was sampledand the hydroxyl value found to be acceptable (32.6). The additionaldistillate collected totaled 1007 parts. The contents of the reactorwere cooled and then diluted with 1295 parts of DOWANOL PM and 1648parts of DOWANOL PM Acetate. The final resin solution was found to havea solids content of 69.5%, determined at 110° C. for one hour, a weightaverage molecular weight of about 2,500 and a number average molecularweight of about 1,200, as determined by gel permeation chromatographyusing a polystyrene standard.

Silica Dispersions Example A

This example describes. the preparation of a colloidal silica dispersionused as a component in the thermosetting compositions of the presentinvention. The colloidal silica dispersion was prepared as follows. Asuitable reaction vessel was equipped for vacuum distillation andflushed with N₂. To the reaction flask was added 3150 g of thepolysiloxane polyol of Example AA described above, 4500 g ofORGANOSILICASOL™ MT-ST colloidal silica (which is commercially availablefrom Nissan Chemicals) and 1440 g of methyl amyl ketone. The meanparticle size of the silica particles was about 10-20 nanometers, asdisclosed at http//www.snowtex.com /organo types.html (Jun. 2, 2000),which is incorporated by reference herein. The resulting mixture wasvacuum distilled at 25° C. for a period of 8 hours.

Example B

This example describes the preparation of a colloidal silica dispersionused as a component in the thermosetting compositions of the presentinvention. The colloidal silica dispersion was prepared as follows. A4-neck reaction flask equipped for vacuum distillation was flushed withN₂. To the reaction flask was added 1501.4 g of the polysiloxane tetroldescribed above, 3752.9 g of ORGANOSILICASOL™ MT-ST colloidal silica(which is commercially available from Nissan Chemicals) and 900.6 g ofmethyl amyl ketone. The resulting mixture was vacuum distilled at 70 mmHg and 31° C.

Adhesion Promoter Compositions

The following Examples C through H describe the preparation of variousadhesion promoting compositions used in the coating compositions of thepresent invention. Each adhesion promoting composition was prepared asdescribed below.

Example C

A four-neck reaction flask equipped with stirrer, temperature probe,Dean Stark trap and reflux condenser was flushed with N2. The followingmaterials were charged to the flask and blended under agitation: 180.4 gof the polysilxoane polyol of Example M, 300.9 g of isopropyl alcoholand 25.8 g of boric acid. The mixture was heated to reflux at atemperature of 79° C., and 200 ml of solvent was removed over 0.25hours. The resulting material was cooled and measured to have 49.8%solids and contained 3.0% water.

Example D

A four-neck reaction flask equipped with stirrer, temperature probe,Dean Stark trap and reflux condenser was flushed with N₂. The followingmaterials were charged to the flask and blended under agitaion: 3241.4 gof the polysiloxane polyol of Example M, 5415.3 g of isopropyl alcoholand 463.9 g of boric acid. The mixture was heated to reflux at atemperature of 73° C., and 3607.7 g of solvent was removed over a periodof 1.5 hours. The resulting material was cooled and measured to have56.0% solids and contained 2.5% water.

Example E

A four-neck reaction flask equipped with stirrer, temperature probe,Dean Stark trap and reflux condenser was flushed with N₂. The followingmaterials were charged to the flask and blended under agitation: 180.3 gof polysiloxane polyol of Example M, 300.7 g of isopropyl alcohol and25.8 g of boric acid. The mixture was heated to reflux at a temperature79° C., and 200 ml of solvent was removed over a period of 0.25 hours.The resulting material was cooled and measured to have 49.5% solids andcontained 3.0% water.

Example F

A four-neck reaction flask equipped with stirrer, temperature probe,Dean Stark trap and reflux condenser was flushed with N₂. The followingmaterials were charged to the flask and blended under agitation: 1575.5g Dowanol PM, and 144.8 g of boric acid. The mixture was heated toreflux at a temperature of 110° C., and held for a period of 2 hours.Thereafter, 632.3 g of solvent was removed over a period of 0.5 hours.The resulting material was cooled and measured to havel 1.2% solids andcontained 5.0% water.

Example G

A four-neck reaction flask equipped with stirrer, temperature probe,Dean Stark trap and reflux condenser was flushed with N₂. The followingingredients were charged to the flask and blended under agitation: 454.7g of acrylic polyol (prepared from 14.5% butyl acrylate, 14.5% butylmethacrylate, 27.6% isobornyl methacrylate, 22.6% hydroxypropylmethacrylate, 20.4% hydroxyethyl methacrylate, and 0.4% acrylic acid,having a resin solids of 69.7%, Mw 3227 and hydroxyl value of 101), 97.2g of isopropyl alcohol and 2.06 g of boric acid. The mixture was heatedto reflux at a temperature of 93° C., and held for a period of 1 hour.Thereafter, 62 g of solvent was removed over a period of 0.25 hours. Theresulting material was cooled and measured 69.3% solids and contained0.1% water.

Example H

A four-neck reaction flask equipped with stirrer, temperature probe,Dean Stark trap and reflux condenser was flushed with N₂. The followingmaterials were charged to the flask and blended under agitation: 360.5 gof the polysiloxane polyol of Example M, 601.7 g of isopropyl alcoholand 13.6 g of aluminum isopropoxide (available from Aldrich ChemicalCo.). The mixture was heated to reflux at a temperature of 81° C., and,thereafter, 401.8 g of solvent was removed over a period of 1 hour. Theresulting material was cooled and measured to have 53.32% solids

Example I

A four-neck reaction flask equipped with stirrer, temperature probe,Dean Stark trap and reflux condenser was flushed with N₂. The followingmaterials were charged to the flask and blended under agitation: 3242.1g of the polysiloxane polyol of Example M, 5411.2 g of isopropyl alcoholand 463.9 g of boric acid. The mixture was heated to reflux at atemperature of 72° C., and 3674.3 g of solvent was removed over a periodof 2 hours. The resulting material was cooled and measured 56.13% solidsand contained 2.5% water.

THERMOSETTING COATING COMPOSITIONS ONE COMPONENT CLEARCOATINGCOMPOSITIONS Example 1

This example describes the preparation of a resinous binder pre-mix usedin the one-package thermosetting coating compositions of Examples 4-6below. Each of the ingredients was added sequentially and mixed undermild agitation. Parts by weight Solid weight Ingredient (grams) (grams)Methyl n-amyl ketone 18.0 — Butyl Cellosolve ® acetate¹ 18.0 — ButylCarbitol ® acetate² 4.0 — TINUVIN ® 384³ 1.58 1.50 TINUVIN ® 400⁴ 1.761.50 TINUVIN ® 292⁵ 0.40 0.40 TINUVIN ® 123⁶ 0.40 0.40 Silica dispersionof Example A 13.2 10.0 LUWIPAL 018⁷ 41.1 30.0 TACT⁸ 9.4 5.0 Polybutylacrylate⁹ 0.50 0.30 Blocked acid catalyst¹⁰ 2.50 1.00¹2-Butoxyethyl acetate solvent commercially available from Union CarbideCorp.²2-(2-Butoxyethoxy) ethyl acetate commercially available from UnionCarbide Corp.³Substituted benzotriazole UV light stabilizer commercially availablefrom Ciba Specialty Chemicals Corp.⁴Substituted triazine UV light stabilizer commercially available fromCiba Specialty Chemicals Corp.⁵Sterically hindered amine light stabilizer commercially available fromCiba Specialty Chemicals Corp.⁶Bis-(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate hinderedaminoether light stabilizer available from Ciba Specialty ChemicalsCorp.⁷High imino, butylated melamine formaldehyde resin commerciallyavailable from BASF Corp.⁸Tris (alkyl carbamoyl) triazine available from Cytec Industries, Inc.The alkyl substituent was mixed methyl and butyl.⁹A flow control agent having a Mw of about 6700 and a Mn of about 2600made in xylene at 62.5% solids available from E. I. duPont de Nemoursand Company.¹⁰Dodecyl benzene sulfonic acid solution, blocked with diisopropanolamine to 91% total neutralization, 40 percent in ethanol.

Example 2

This example describes the preparation of a resinous binder pre-mix usedin the one-package thermosetting coating composition of Examples 7-9described below. Each of the ingredients was added sequentally and mixedunder mild agitation. Parts by weight Solid weight Ingredient (grams)(grams) Methyl n-amyl ketone 16.0 — Butyl Cellosolve ® acetate 16.0 —Butyl Carbitol ® acetate 3.50 — TINUVIN ® 928¹ 3.00 3.00 TINUVIN ® 2920.40 0.40 Silica Dispersion of 10.3 7.0 Example B RESIMENE ® 757² 41.240.0 Polybutyl acrylate 0.50 0.30 Blocked acid catalyst 2.50 1.00¹2-(2H-Benzotriazol-2yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol# UV absorber available from Ciba Specialty Chemicals Corp.²Methylated and butylated melamine-formaldehyde resin available fromCytec Industries, Inc.

Example 3

This example describes the preparation of a resinous binder pre-mix usedin the preparation of thermosetting coating compositions of Examples 7-9described below. The resins were admixed and blended under mildagitation. Parts by weight Solid weight Ingredient (grams) (grams)Carbamoylated acrylic¹ 44.4 28.0 Carbamoylated polyester² 38.9 28.0¹(58% butyl methacrylate/40% hydroxypropyl acrylate/2% methyl styrenedimer) 64% solids in a solvent blend of (50% DOWANOL PM/50% propanoicacid, 3-ethoxy ethyl ester),# 75% carbamoylated with methyl carbamate.²(10.6% trimethylol propane/22.7% 2,2,4-trimethyl-1,3-pentanediol/17.5%neopentyl glycol/49.2% hexahydrophthalic anhydride) 69% solids in asolvent blend of (44%# Dowanol PM/56% Dowanol PM Acetate) 75% carbamoylated with methylcarbamate.

The preparation of various one-package thermosetting coatingcompositions are described below in the following Tables 1 and 2. Theamounts listed are the total parts by weight in grams and the amountwithin parenthesis are percentages by weight based on weight of solids.Each component was mixed sequentially with agitation. Comparativecoating compositions which do not contain a boron-containing compoundare indicated using an “*”. TABLE 1 Ingredient Example 4* Example 5Example 6 Example 1 pre-mix 110.8 110.8 110.8 (50.1) (50.1) (50.1)Acrylic resin¹ 89.9 88.4 83.7 (58.0) (57.0) (54.0) Siloxane Borate of —2.01 8.0 Example C (1.00) (4.00) Reduction: Methyl n-amyl ketone 5.44.79 3.07 Butyl Cellosolve ® 5.4 4.79 3.07 acetate Butyl Carbitol ®acetate 1.2 1.06 0.68 Spray viscosity² (sec) 28.4 28.2 28.1 Painttemperature (° F.) 73.3 73.5 73.1 Theory % Solids³ 50.8 51.0 51.6¹Acrylic resin (30% styrene, 19.9% hydroxyethyl methacrylate, 28.7%CarduraE (available from Shell Chemical Co.), 9.5% acrylic acid, and 12%ethylhexyl acrylate) at# 65% solids in SOLVESSO 100 (available from Exxon Chemicals America),prepared in Example A of U.S. Pat. No. 5,965,670.²Viscosity measured in seconds with a #4 FORD efflux cup at ambienttemperature.³Theory % Solids of a coating is determined by taking the solid weightof the coating formulation divided by the sum of the parts by weight ofthe coating# formulation and the reducing solvent weight

TABLE 2 Ingredient Example 7* Example 8 Example 9 Example 2 pre-mix 93.493.4 93.4 (51.7) (51.7) (51.7) Example 3 pre-mix 83.3 81.8 77.4 (56.0)(55.0) (52.0) Siloxane Borate of — 1.79 7.1 Example D (1.00) (4.00)Methyl n-amyl ketone 2.00 — — Butyl Cellosolve ® 2.00 — — acetate ButylCarbitol ® acetate 0.50 — — Reduction Information: Methyl n-amyl ketone3.03 4.7 3.83 Butyl Cellosolve ® 3.03 4.7 3.83 acetate Butyl Carbitol ®acetate 0.67 1.04 0.85 Spray viscosity¹(sec) 28.4 28.7 28.1 Painttemperature (° F.) 72.4 72.3 72.0 Theory % Solids² 57.3 57.5 57.8¹Viscosity measured in seconds with a #4 FORD efflux cup at ambienttemperature.²Theory % Solids of a coating is determined by taking the solid weightof the coating formulation divided by the sum of# the parts by weight of the coating formulation and the reducingsolvent weight.Testing

The film forming compositions of Examples 4-9 were spray applied to apigmented basecoat to form color-plus-clear composite coatings overprimed electrocoated steel panels. The panels used were cold rolledsteel panels (size 4 inches×12 inches (10.16 cm by 30.48 cm)). The steelpanels for Examples 4-6 were coated with ED5000 electrocoat, availablefrom PPG Industries, Inc, and SUPERMAR primer, available fromHerberts/DuPont. The ED5000 electrocoat test panels are available asAPR22986 from ACT Laboratories, Inc. of Hillsdale, Michigan. Examples7-9 utilized steel panels that were coated with ED5240 electrocoat andFCP6579 primer, both available from PPG Industries, Inc. The test panelsare available as APR40017 from ACT Laboratories, Inc. of Hillsdale,Mich.

The basecoat used for Examples 4-6 was Nero Vulcano UR806/A, blackpigmented solvent-based acrylic/melamine basecoat, available from PPGIndustries, Inc. Examples 7-9 used ODCT6373 Ebony Black, a blackpigmented solvent-based acrylic/melamine basecoat, available from PPGIndustries, Inc.

The Nero Vulcano UR806/A basecoat was automated spray applied in onecoat to the electrocoated and primed steel panels at ambient temperature(about 70° F. (21° C.)). A dry film thickness of about 0.5 to 0.7 mils(about 13 to 18 micrometers) was targeted. After the basecoatapplication, a ninety second air flash at ambient temperature was givenbefore applying the clearcoat. The ODCT6373 Ebony Black basecoat wasautomated spray applied in two coats to the electrocoated and primedsteel panels at ambient temperature (about 70° F. (21° C.)). A ninetysecond air flash at ambient temperature was given between the twobasecoat applications. A dry film thickness of about 0.6 to 0.8 mils(about 15 to 20 micrometers) was targeted. After the second basecoatapplication, a ninety second air flash at ambient temperature was givenbefore applying the clearcoat.

The clear coating compositions of Examples 4-9 were each automated sprayapplied to a basecoated panel at ambient temperature in two coats with aninety second ambient flash between applications. Examples 4-6 weretargeted for a 1.5 to 1.7 mils (about 38 to 43 micrometers) dry filmthickness, and Examples 7-9 were targeted for a 1.7 to 1.9 mils (about43 to 48 micrometers) dry film thickness. All coatings were allowed toair flash at ambient temperature for ten minutes. Panels prepared fromeach coating were baked for thirty minutes at 285° F. (141° C.) to fullycure the coating(s). The panels were baked in a horizontal position.

To test for recoat adhesion, an original basecoated and clearcoatedpanel, as described above, was given another layer of basecoat andclearcoat or clearcoat only. Examples 4-6 were recoated with NeroVulcano UR806/A and Examples 4-6, depending on the respective originalpanel. Examples 7-9 were recoated with ODCT6373 Ebony Black and Examples7-9, depending on the respective original panel. For example, an Example4 clearcoat over Nero Vulcano UR806/A original (prepared above) wasrecoated with Nero Vulcano UR806/A and Example 4 clearcoat. Half of anoriginal panel from each clear coating was basecoated and clearcoatedand the other half of the panel was clearcoated only. To recoat thepanels half and half, the bottom halves of the original panels werecovered with aluminum foil and then the respective basecoats wereautomated spray applied as described above. The foil was removed,resulting in an original panel with the upper half coated in basecoatand the bottom half still with only the original coating layers. Therespective clearcoat was then automated spray applied to the entirepanel as described above. The resulting panels were half coated inbasecoat/clearcoat from the original spray application and another layerof basecoat/clearcoat from the recoat spray application (B/C//B/C). Theother half of the resulting panel was coated in basecoat/clearcoat fromthe original spray application and another layer of clearcoat from therecoat spray application (B/C//C).

Test results for the coatings are reported below in Table 3. Asmentioned above the coating compositions of Examples 4-6 were appliedover Nero Vulcano UR806/A basecoat and Examples 7-9 were applied overODCT6373 Ebony Black basecoat. TABLE 3 Adhesion Promoter (B) ElementalWindshield Weight % Adhesion³ Example on Resin 20° Recoat Adhesion² (%cohesive # Solids Gloss¹ B/C//B/C B/C//C failure) 4* 0 91 0 td 0 td — 50.02 91 2/3 0 — 6 0.08 91 4+ 4 — 7* 0 86 2+ 0 0 8 0.02 86 5− 3+ 100 90.08 84 5 5 100¹20° gloss was measured with a Statistical Novo-Gloss 20° gloss meter,available from Paul N. Gardner Company, Inc.²Recoat adhesion tests the adhesion of the recoat layer (eitherbasecoat/clearcoat or clearcoat only) to the original layers(steel/electrodeposition/primer/basecoat/clearcoat). A multi-blade clawwith 2.0 mm spaced teeth (blade and handle/blade holder are availablefrom Paul N. Gardner Company, Inc.) was used to scribe the curedcoating. Two sets of scribes were made by scribing the second set on topof and# perpendicular to the first set. Detached flakes and ribbons of coatingwere wiped off the panel and strapping tape (3M #898 # available fromMinnesota, Mining and Manufacturing Co. - 3M) was smoothed firmly overthe crosshatch marking. Within 90 seconds of application, the tape wasremoved in one continuous motion directed toward the tester and asparallel to the panel as possible. The scribed area was inspected andrated for removal of the recoat layer to the substrate according to thefollowing scale:5 = The edges of the cuts are completely smooth and none of the latticesquares is detached.4 = Small flakes of coating are detached at intersections. Less thanfive percent of the area is affected.3 = Small flakes of the coating are detached along edges and atintersections of cuts. The area affected is five to fifteen percent ofthe lattice.2 = The coating has flaked along the edges and on parts of the squares.The area affected is fifteen to thirty-five percent of the lattice.1 = The coating has flaked along the edges of cuts in large ribbons andwhole squares have detached. The area affected is thirty-five tosixty-five percent of the lattice.0 = Flaking and detachment worse than rating 1. Over sixty-five percentof the lattice is affected.Td = Total delamination,³The adhesion between a coating and a windshield adhesive used in theautomotive industry was determined using the Quick Knife test. Within 1to 4 hours of the final thirty minute bake cycle, a bead of the BETASEAL15625 urethane adhesive (Supplied by Essex Specialty Products Inc.) wasapplied to the surface of the clearcoat of a basecoated and clearcoatedpanel, prepared as described above. The plastic nozzle# (supplied with adhesive) was prepared for the urethane by cutting thetip at ˜80° angle. The opening measured approximately 5 mm in diameter.On the long end of the cut edge, a notch approximately 5 mm wide by 2 mmhigh was cut. The tube of urethane was placed in a battery poweredcaulking gun and a small amount was squeezed from the tube into a papercup for disposal. The caulking gun was set at ˜90% speed for a steadyflow of adhesive. # The plastic tip was placed on the panel with thenotch facing away from the person applying the # bead. With the tip heldfirmly on the panel at the same angle (80°) # as the cut nozzle, asteady bead was applied down the length of the panel. The bead was flatwhere it contacted the panel. After the bead was laid, the panel wasplaced in a ventilated hood where it remained undisturbed for at least72 hours @ 20-50% R.H. in order to cure. After the bead cured, theadhesive bead was cut with a razor blade knife. A small section was cutat the beginning of the bead to make it easier to grasp. To cut thebead, # the small beginning section was pulled back at approximately a180° angle and slices were # made in the adhesive at a 60° to 80° anglein a quick motion. The blade was kept in contact with the clearcoat atall times during. The adhesive bead continued to be pulled while theadhesive was being cut at ˜½″ intervals. A minimum of 10 cuts was made.After making slices to the adhesive bead, the panel was rated for %Cohesive Failure (% C.F.) of the bead to the panel. (Cohesive Failure #occurs when the integrity of the adhesive bead is lost as a result ofcutting and pulling rather than the bond between the adhesive bead andthe clearcoat surface.) Failures were reported as a total % along thebead. For example, if there was 20% of the urethane remaining on thepanel, then it was reported as 20% C.F. and if the entire bead can bepulled off, it was considered to be 0% C.F. The desired result was aminimum of 90% or higher cohesion.

The data presented above in Table 3 illustrate that recoat adhesion forthe one-package coating compositions of the present invention improvesas the amount of adhesion promoting composition increases in thecomposition, while similar comparative compositions which do not containthe polysiloxane borate have poor or no recoat adhesion. Further, thedata illustrate that while the comparative composition of Example 7exhibits very poor (0%) MVSS cohesive failulre, the compositions of thepresent invention (Examples 8 and 9) exhibit excellent (100%) cohesivefaillure.

Examples 10 through 13

The following Examples 10 through 13 presented in Table 4 below describethe preparation of thermosetting coating compositions based on epoxycontaining acrylic resins cured with acid functional curing agents incombination with aminoplast resins. The compositions were prepared byadmixing the following ingredients under mild agitation. Note, thosecomparative compositions which do not contain a boron-containingcompound (i.e., Comparative Examples 10 and 13) are designated with an“*”. TABLE 4 Example 10* Example 11 Example 12 Example 13* Solids SolidsSolids Solids Resin + Soln. Resin + Soln. Resin + Soln. Resin + Soln.Materials Additive Wt. Additive Wt. Additive Wt. Additive Wt. n-pentyl —25 — 25 — 25 — 15 propionate¹ DOWANOL ® — — — — — — — 11.2 DPM²TINUVIN ®-328³ 3 3 3 3 3 3 2.7 2.7 Colloidal silica 10.5 10.5 10.5 — —dispersion of Example A 60% GMA resin⁴ 42.9 67 39.05 61 37.05 58 — — 50%GMA resin⁵ — — — — — — 56.25 87.9 Primary amyl — — — — — — — 4.1alcohol⁶ CYMEL 202⁷ 3 3.8 3 3.8 3 3.8 2.05 2.6 CYLINK ® 2000⁸ 10 20 1020 10 20 — — Fumed silica — — — — — — 12.9 dispersion⁹ Isostearic Acid¹⁰4 4 4 4 4 4 4.1 4.1 PENTEK¹¹ 34.25 50.4 34.1 50 32.1 47.2 34.2 50.3Siloxane Borate — — 4 8.1 8 16.2 — — of Example A TINUVIN ®123 0.4 0.40.4 0.4 0.4 0.4 0.35 0.35 Polybutyl — — — — — — 0.51 0.85 acrylateDISPARLON — — — — — — 0.04 0.08 OX-60¹² Multiflow (50% 0.025 0.05 0.0250.05 0.025 0.05 0.09 0.18 sol. Of MODAFLOW)¹³ Di-methyl 0.3 0.3 0.3 0.30.3 0.3 0.32 0.32 cocoamine¹⁴¹Available from Dow Chemical Co.²Dipropylene glycol monomethyl ether, available from Dow Chemical Co.³2-(2′-Hydroxy-3′,5′-dtert-amylphenyl) benzotriazole UV light stabilizeravailable from Ciba Specialty Chemicals Corp.⁴Acrylic resin comprising 60% glycidyl methacrylate, 31% n-butylmethacrylate, 0.2% methyl methacrylate, 7% styrene, 2%diphenyl-2,4-methyl-4 pentene-1, 66% solids in dipropylene glycolmonomethyl ether and n-amyl propionate.⁵Acrylic resin comprising 50% glycidyl methacrylate, 41% n-butylmethacrylate, 0.2% methyl methacrylate, 7% styrene, 2%diphenyl-2,4-methyl-4 pentene-1, 64% solids in dipropylene glycolmonomethyl ether and n-amyl propionate.⁶Available from Dow Chemical Co.⁷Melamine available from Cytec Industries, Inc.⁸Available from Cytec Industries, Inc.⁹R-812 silica from Degussa dispersed in n-amyl alcohol and a trimethylolpropane/methylhexahydrophthalic anhydride half ester of Example G inU.S. Pat. No. 5,256,452.¹⁰Available from Uniqema.¹¹Polyester prepared from 83% 4-methyl hexahydrophthalic anhydride and17% pentaerythritol, 67% solids in n-propyl alcohol and n-amylpropionate.¹²Available from Kusumoto, a King Industries distributor.¹³Available from Solutia.¹⁴Available from Albemarle Corp.

The clearcoats prepared as described above were reduced with DOWANOL®DPM to a spray viscosity of 26 seconds at ambient temperature(approximately 76° F. (26° C.)), with a Ford #4 cup.

Testing

The film forming compositions of Examples 10-13 were spray applied to apigmented basecoat to form color-plus-clear composite coatings overelectrocoated steel panels. The panels used were cold rolled steelpanels (size 4 inches×12 inches (10.16 cm by 30.48 cm)). The steelpanels for Examples 10-13 were coated with ED5000 electrocoat, availablefrom PPG Industries, Inc. These prepared test panels are available asAPR23884 from ACT Laboratories, Inc. of Hillsdale, Mich.

The basecoat used for Examples 10-13 was HWB-9517, black pigmentedwaterborne basecoat, available from PPG Industries, Inc. The HWB-9517basecoat was automated spray applied in one coat to the electrocoatedsteel panels at ambient temperature (i.e., at approximately 76° F. (25°C.) and 30% relative humidity). A dry film thickness of about 0.5 to 0.7mils (about 13 to 18 micrometers) was targeted. The basecoat was allowedto flash ambiently for about 5minutes and then prebaked for five minutesat 200° F. (93° C.).

The clear coating compositions of Examples 10-13 were each automatedspray applied to a basecoated panel at ambient temperature in two coatswith a 60 second ambient flash between applications. Coatings ofExamples 10-13 were targeted for a 1.8 to 2 mils (about 46 to 51micrometers) dry film thickness. All coatings were allowed to air flashat ambient temperature for ten minutes. Panels prepared from eachcoating were baked for thirty minutes at 285° F. (141° C.) to fully curethe coating(s). The panels were baked in a horizontal position.

To test for recoat adhesion, an original basecoated and clearcoatedpanel, as described above, was given another layer of basecoat andclearcoat or clearcoat only. Examples 10-13 were recoated with HWB-9517basecoat. To recoat the panels half and half, the right halves of theoriginal panels were covered with masking tape and then the respectivebasecoats were automated spray applied as described above. The tape wasremoved, resulting in an original panel with the right half coated inbasecoat and the left half still with only the original coating layers.The respective clearcoat was then automated spray applied to the entirepanel as described above. The resulting panels were half coated inbasecoat/clearcoat from the original spray application and another layerof basecoat/clearcoat from the recoat spray application (B/C//B/C). Theother half of the resulting panel was coated in basecoat/clearcoat fromthe original spray application and another layer of clearcoat from therecoat spray application (B/C//C). Test data is presented below in thefollowing Table 5. TABLE 5 Elemental MVSS Recoat Recoat weight %primerless Adhesion Adhesion Clearcoat 20° on Resin adhesion % % pass %pass composition Gloss Solids pass B/C//B/C B/C//C Example 11 72 0.08data 30 50 unavailable Example 12 72 0.16 88 100 100 Example 10* 83 0100 0 0 Example 13* 83 0 100 100 100*Comparative examples

The data presented in Table 5 above illustrate that the epoxy-acid clearcoat controls of Comparative Examples 10 and 13 pass MVSS primerlessadhesion. However, these same the clearcoating of Example 10 exhibitsvery poor recoat adhesion when recoated either with a subsequentlyapplied repair basecoat/clearcoat system or a repair clearcoat. Bycontrast, the coating compositions of the present invention whichcontain the polysiloxane borate, exhibit improved recoat adhesion and100% recoat adhesion (see Examples 11 and 12, respectively).

TWO-COMPONENT CLEARCOATING COMPOSITIONS Comparative Example 14

This comparative example describes the preparation of a two-componentclearcoat composition which does not contain an adhesion promotingcompound. The coating composition was prepared by admixing the followingingredients sequentially under mild agitation. Parts by Weight SolidWeight Ingredient (grams) (grams) Methyl n-amyl ketone 30.0 — ButylCellosolve ® acetate 10.0 — Butyl Carbitol ® acetate 5.0 — Tinuvin 9283.0 3.0 Tinuvin 292 0.5 0.5 Silica dispersion of Example A 8.8 6.7Acrylic Resin¹ 58.2 42.2 CYMEL ® 202 18.8 15.0 Polysiloxane polyol ofExample AA 11.0 11.0 Phenyl Acid Phosphate Catalyst² 0.7 0.5DesmodurN3300⁴ 27.1 27.1¹Acrylic polyol prepared from 14.5% butyl acrylate, 14.5% butylmethacrylate, 27.6% isobornyl methacrylate, 22.6% hydroxypropylmethacrylate, 20.4%# hydroxyethyl methacrylate, and 0.4% acrylic acid, having resin solidsof 69.7%, Mw 3227 and a hydroxyl value of 101.²Phenyl acid phosphate solution, 75 percent in isopropanol.³Isocyanurate of hexamethylene diisocyanate available from Bayer Corp.

Example 15

This example describes the preparation of a two-component clearcoatcomposition of the present invention which contains a siloxane borate asan adhesion promoting compound. The coating composition was prepared byadmixing the following ingredients sequentially under mild agitation.Parts by Weight Solid Weight Ingredient (grams) (grams) Methyl n-amylketone 30.0 — Butyl Cellosolve ® acetate 10.0 — Butyl Carbitol ® acetate5.0 — Tinuvin 928 3.0 3.0 Tinuvin 292 0.5 0.5 Silica dispersion ofExample A 8.8 6.7 Acrylic Resin of Example 14 58.2 42.2 Cymel 202 18.815.0 Polysiloxane polyol of Example AA 10.0 10.0 Siloxane Borate ofExample E 2.4 1.0 Phenyl Acid Phosphate Catalyst 0.7 0.5 DesmodurN330027.1 27.1

Example 16

This example describes the preparation of a two-component clearcoatcomposition of the present invention which contains a siloxane borate asan adhesion promoting compound. The coating composition was prepared byadmixing the following ingredients sequentially under mild agitation.Parts by Weight Solid Weight Ingredient (grams) (grams) Methyl n-amylketone 30.0 — Butyl Cellosolve ® acetate 10.0 — Butyl Carbitol ® acetate5.0 — Tinuvin 928 3.0 3.0 Tinuvin 292 0.5 0.5 Silica dipersion ofExample A 8.8 6.7 Acrylic Resin of Example 14 58.2 42.2 Cymel 202 18.815.0 Polysiloxane polyol of Example AA 9.0 9.0 Siloxane Borate ofExample E 4.9 2.0 Phenyl Acid Phosphate Catalyst 0.7 0.5 DesmodurN330027.1 27.1

Example 17

This example describes the preparation of a two-component clearcoatcomposition of the present invention which contains a siloxane borate asan adhesion promoting compound. The coating composition was prepared byadmixing the following ingredients sequentially under mild agitation.Parts by Weight Solid Weight Ingredient (grams) (grams) Methyl n-amylketone 30.0 — Butyl Cellosolve ® acetate 10.0 — Butyl Carbitol ® acetate5.0 — Tinuvin 928 3.0 3.0 Tinuvin 292 0.5 0.5 Silica dispersion ofExample A 8.8 6.7 Acrylic Resin of Example 14 58.2 42.2 Cymel 202 18.815.0 Polysiloxane polyol of Example AA 7.0 7.0 Siloxane Borate ofExample E 9.8 4.0 Phenyl Acid Phosphate Catalyst 0.7 0.5 DesmodurN330027.1 27.1

Example 18

This example describes the preparation of a two-component clearcoatcomposition of the present invention which contains a boric acid as anadhesion promoting compound. The coating composition was prepared byadmixing the following ingredients sequentially under mild agitation.Parts by Weight Solid Weight Ingredient (grams) (grams) Methyl n-amylketone 30.0 — Butyl Cellosolve ® acetate 10.0 — Butyl Carbitol ® acetate5.0 — Tinuvin 928 3.0 3.0 Tinuvin 292 0.5 0.5 Silica dispersion ofExample A 8.8 6.7 Acrylic Resin of Example 14 58.2 42.2 Cymel 202 18.815.0 Polysiloxane polyol of Example AA 11.0 11.0 Boric acid (20%solution in 1.3 0.3 methanol) Phenyl Acid Phosphate Catalyst 0.7 0.5DesmodurN3300 27.1 27.1

Example 19

This example describes the preparation of a two-component clearcoatcomposition of the present invention which contains a boric acid as anadhesion promoting compound. The coating composition was prepared byadmixing the following ingredients sequentially under mild agitation.Parts by Weight Solid Weight Ingredient (grams) (grams) Methyl n-amylketone 30.0 — Butyl Cellosolve ® acetate 10.0 — Butyl Carbitol ® acetate5.0 — Tinuvin 928 3.0 3.0 Tinuvin 292 0.5 0.5 Silica dispersion ofExample A 8.8 6.7 Acrylic Resin of Example 14 58.2 42.2 Cymel 202 18.815.0 Polysiloxane polyol of Example AA 11.0 11.0 Boric acid (20%solution in 5.0 1.0 methanol) Phenyl Acid Phosphate Catalyst 0.7 0.5DesmodurN3300 27.1 27.1

Example 20

This example describes the preparation of a two-component clearcoatcomposition of the present invention which contains triisopropyl borateas an adhesion promoting compound. The coating composition was preparedby admixing the following ingredients sequentially under mild agitation.Parts by Weight Solid Weight Ingredient (grams) (grams) Methyl n-amylketone 30.0 — Butyl Cellosolve ® acetate 10.0 — Butyl Carbitol ® acetate5.0 — Tinuvin 928 3.0 3.0 Tinuvin 292 0.5 0.5 Silica dispersion ofExample A 8.8 6.7 Acrylic Resin of Example 14 58.2 42.2 Cymel 202 18.815.0 Polysiloxane polyol of Example AA 11.0 11.0 Triisopropyl Borate¹0.9 0.9 Phenyl Acid Phosphate Catalyst 0.7 0.5 DesmodurN3300 27.1 27.1¹Available from Aldrich Chemical Co.

Example 21

This example describes the preparation of a two-component clearcoatcomposition of the present invention which contains borate ester as anadhesion promoting compound. The coating composition was prepared byadmixing the following ingredients sequentially under mild agitation.Parts by Weight Solid Weight Ingredient (grams) (grams) Methyl n-amylketone 30.0 — Butyl Cellosolve ® acetate 10.0 — Butyl Carbitol ® acetate5.0 — Tinuvin 928 3.0 3.0 Tinuvin 292 0.5 0.5 Silica dispersion ofExample A 8.8 6.7 Acrylic Resin of Example 14 58.2 42.2 Cymel 202 18.815.0 Polysiloxane polyol of Example AA 11.0 11.0 Bonc Acid Ester ofExample F 2.2 0.3 Phenyl Acid Phosphate Catalyst 0.7 0.5 DesmodurN330027.1 27.1

Example 22

This example describes the preparation of a two-component clearcoatcomposition of the present invention which contains an acrylic borate asan adhesion promoting compound. The coating composition was prepared byadmixing the following ingredients sequentially under mild agitation.Parts by Weight Solid Weight Ingredient (grams) (grams) Methyl n-amylketone 30.0 — Butyl Cellosolve ® acetate 10.0 — Butyl Carbitol ® acetate5.0 — Tinuvin 928 3.0 3.0 Tinuvin 292 0.5 0.5 Silica dispersion ofExample A 8.8 6.7 Boric Acid Ester of Example G 60.9 42.2 Cymel 202 18.815.0 Polysiloxane polyol of Example AA 11.0 11.0 Phenyl Acid PhosphateCatalyst 0.7 0.5 DesmodurN3300 27.1 27.1

Example 23

This example describes the preparation of a two-component clearcoatcomposition of the present invention which contains a siloxane aluminumisopropoxide as an adhesion promoting compound. The coating compositionwas prepared by admixing the following ingredients sequentially undermild agitation. Parts by Weight Solid Weight Ingredient (grams) (grams)Methyl n-amyl ketone 30.0 — Butyl Cellosolve ® acetate 10.0 — ButylCarbitol ® acetate 5.0 — Tinuvin 928 3.0 3.0 Tinuvin 292 0.5 0.5 Silicadispersion of Example A 8.8 6.7 Acrylic Resin of Example 14 58.2 42.2Cymel 202 18.8 15.0 Polysiloxane polyol of Example AA — — SiloxaneAluminum isopropoxide of 42.9 22.9 Example H Phenyl Acid PhosphateCatalyst 0.7 0.5 DesmodurN3300 27.1 27.1

The clearcoats Examples 14 through 23 described above were reduced inviscosity to about 25 seconds on a #4 Ford efflux cup at ambienttemperature using methyl n-amyl ketone.

Testing

The film forming compositions of Examples 14-23 were spray applied to apigmented basecoat to form color-plus-clear composite coatings overprimed electrocoated steel panels. The panels used were cold rolledsteel panels (size 4 inches×12 inches (10.16 cm by 30.48 cm)). The steelpanels for Examples 14-23 were coated with ED5050B electrocoat,available from PPG Industries, Inc, and 1177225A primer surfacer, alsoavailable from PPG Industries, Inc or coated with ED5000 electrocoat,available from PPG Industries, Inc, and GPXH5379 primer surfacer, alsoavailable from PPG Industries, Inc. The test panels are available asAPR39754 or APR39375 from ACT Laboratories, Inc. of Hillsdale, Mich.

The basecoat used for Examples 14-23 was Obsidian Schwarz, blackpigmented waterborne basecoat, available from BASF Corporation. TheObsidian Schwarz basecoat was automated spray applied in two coats withapproximately 30 second flash between coats to the electrocoated andprimed steel panels at about 70° F. (21° C.) temperature and about 60%relative humidity. A dry film thickness of about 0.5 to 0.6 mils (about12 to 16 micrometers) was targeted. The basecoat was allowed to flashambiently for about five minutes and then prebaked for five minutes at176° F. (80° C.).

The clear coating compositions of Examples 14-23 were each automatedspray applied to a basecoated panel at ambient temperature in two coatswith about a 30 second ambient flash between coats. Examples 1-10 weretargeted for a 1.5 to 2.0 mils (about 38 to 51 micrometers) dry filmthickness. All coatings were allowed to air flash at ambient temperaturefor ten minutes. Panels prepared from each coating were baked for 30minutes at 285° F. (141° C.) to fully cure the coating(s). The panelswere baked in a horizontal position.

To test for recoat adhesion, an original basecoated and clearcoatedpanel, as described above, was given another layer of basecoat andclearcoat or clearcoat only. With the condition of sanding, the righthalf of the panel was sanded with 1200 grit sand paper and the left halfwas not sanded thus giving sanded and non-sanded areas. Half of anoriginal panel from each clear coating was basecoated and clearcoatedand the other half of the panel was clearcoated only. To recoat thepanels half and half, the bottom halves of the original panels werecovered with aluminum foil and then the top halves were recoated withObsidian Schwarz basecoat using the same conditions as above. The foilwas removed, resulting in an original panel with the upper half coatedin basecoat and the bottom half still with only the original coatinglayers. The respective clearcoat was then automated spray applied to theentire panel as described above. The resulting panels were half coatedin basecoat/clearcoat from the original spray application and anotherlayer of basecoat/clearcoat from the recoat spray application(B/C//B/C). The other half of the resulting panel was coated inbasecoat/clearcoat from the original spray application and another layerof clearcoat from the recoat spray application (B/C//C). Test data isreported below in the following Table 6. TABLE 6 Recoat Adhesion - CrossHatch Adhesion promoter 30/285° F. (141° C.) // 30/285° F. (141° C.)Elemental Weight % Sanded Non-Sanded Example # on Resin Solids 20° GlossB/C//B/C B/C//C B/C//B/C B/C//C 14* 0 84 5 5 0 0 15 0.02 84 5 5 5 0 160.04 85 5 5 5 0 17 0.08 84 5 5 5 5− 18 0.04 84 5 5 5 0 19 0.16 85 5 5 55− 20 0.04 85 — — 5 0 21 0.04 85 — — 5 0 22 0.03 85 — — 5 0 23 0.10 82 55 5 0*Designates a comparative example.

The data presented above in Table 6 illustrate that the inclusion in atwo-component clearcoating composition of the adhesion promotingcomposition of Examples C through H above provide excellent adhesionwhere a basecoat/clearcoat system is recoated with a repairbasecoat/clearcoat system. Further, the data for Examples 14-22illustrate that the inclusion of the polysiloxane borate and boric acid(where the composition also comprises a polysiloxane) at levels ofelemental boron of 0.08 or greater, show excellent adhesion where abasecoat/clearcoat system is repaired with a clearcoat.

Basecoating Compositions

Examples 24 and 25 describe the preparation of basecoating compositions.Comparative Example 24 describes the preparation of an aqueousbasecoating composition which does not contain the polysiloxane as anadhesion promoter. Example 25 describes the preparation of apigment-containing basecoating composition according to the presentinvention which contains a polysiloxane borate as an adhesion promoter.

Comparative Example 24

An aqueous silver metallic basecoat composition was prepared in threestages as follows. The first four components of the “organic portion” ofthe basecoat were combined and then agitated until well dispersed. Thenext two ingredients were then added under agitation and mixed for 20minutes, followed by addition of the last ingredient which was addedunder agitation until dispersed.

In a separate container, the “thickener portion” of the basecoat wasprepared by combining the three ingredients under agitation and mixedfor 20 minutes.

The “aqueous portion” of the basecoat was assembled by adding eachaqueous component under agitation and mixing for approximately 10minutes until well blerided. The organic portion was then added slowlyto the aqueous portion and agitated for 20 minutes. The pH of theadmixture was adjusted to 8.5-8.7 with a 50% solution of dimethylethanolamine and deionized water. The thickener portion was then added andagain the pH was adjusted. The resulting basecoating composition wasallowed to equilibrate for 24 hours before the final pH adjustment wasmade. At that time, the basecoating composition was reduced in viscosityto 25-27 seconds using a 4 Ford Cup with deionized water beforespraying. Pigment Additive Solution Resin Solids Solids Solids Weight(grams) (grams) (grams) (grams) Organic Portion N-Butoxypropanol 0 0 045.04 Cymel 303LF¹ 25 0 0 25 Cymel 385² 5 0 0 6.25 TINUVIN ® 1130³ 0 01.4 1.40 Aqua Paste 3620-D23⁴ 1.5 15.1 0 23.50 Aqua Paste 3700-A23⁵ 0.44.3 0 6.50 Phosphatized Epoxy⁶ 0 0 0.24 0.39 Aqueous Portion SHELLSOL ®071⁷ 0 0 0 6 Latex resin⁸ 58.1 0 0 140 Deionized water 0 0 0 50 AcrylicGrind 6 0 0 23.1 Dispersion⁹ 50% dimethanolamine 0 0 0 2.2 solutionThickener Solution Deionized water 0 0 0 10 50% DMEA Solution 0.0 0.00.0 2.5 Oligomeric Polyester¹⁰ 4 0.0 0.0 5¹Melamine available from Cytec Industries, Inc.²Melamine available from Cytec Industries, Inc.³Substituted benzotriazole UV light absorber available from CibaAdditives.⁴Aqua Paste, treated aluminum available from Silberline ManufacturingCo., Inc.⁵Aqua Paste, treated aluminum available from Silberline ManufacturingCo., Inc.⁶Phosphatized epoxy prepared from EPON ®828, a polyglycidyl ether ofBisphenol A, available form Shell Oil and Chemical Co.; reacted withphosphoric acid at an 83:17 weight ratio.⁷Mineral spirits available from Shell Chemical Co.⁸Latex prepared as follows: (I) a polyester resin was prepared by addingto a four-neck round bottom flask equipped with a thermometer,mechanical stirrer, condenser, dry nitrogen sparge, and a heatingmantle, the following ingredients: 1103.0 g isostearic acid,# 800.0 g pentaerythritol, 470.0 g crotonic # acid, 688.0 g phthalicanhydride, 6.1 g dibutyltin oxide, 6.1 g triphenyl phosphite, 1170.0 gbutyl acrylate, and 4.0 g lonol (butylated hydroxytoluene). The firstsix ingredients were stirred in the flask at 210° C. until 245 ml ofdistillate was collected and # the acid value dropped to 4.6. Thematerial was cooled to 77° C. and the last two ingredients were stirredin. The final product was a viscous yellow liquid with a hydroxyl valueof 54.0, a Gardner-Holdt viscosity of Z+, a weight average molecularweight of # 45,600, and a non-volatile content of 70.2%; (II) apre-emulsion was prepared by stirring together the following #ingredients: 286.0 g of the polyester of (I), 664.0 g butyl acrylate,30.0 g ethylene glycol dimethacrylate, 20.0 g acrylic acid, 46.4 gdodecylbenzenesulfonic acid (70% in isopropanol), 14.3 gdimethylethanolamine, and 1000.0 g water. The pre-emulsion was passedonce # through a Microfluidizer © M110T at 8000 psi and transferred to a# fourneck round bottom flask equipped with an overhead stirrer,condenser, thermometer, and a nitrogen atmosphere. 150.0 g of water usedto rinse the Microfluidizer © was added to the flask. The polymerizationwas initiated by adding 3.0 g # of isoascorbic acid and 0.02 g offerrous ammonium sulfate dissolved in 120.0 g water followed by a thirtyminute addition of 4.0 g of 70% t-butyl hydroperoxide dissolved in 115.0g of water. The reaction exothermed from 23° C. to 80° C. # After thetemperature was reduced to 30° C., 36 g of 33.3% aqueous #dimethylethanolamine was added followed by 2.0 g of Proxel GXL (Biocideavailable from ICI Americas, Inc.) in 8.0 g of water. The final pH ofthe # latex was 8.0, the nonvolatile content was 42.0%, the particlesize was 105 nm, and the Brookfield # viscosity was 12 cps (spindle #1,50 rpm).⁹Acrylic dispersion grind vehicle (35% butyl acrylate, 30% styrene, 18%butyl methacrylate, 8.5%# hydroxyethyl acrylate, and 8.5% acrylic acid).¹⁰Prepared according to U.S. Pat. No. 5,356,973, Example A.

Example 25

This example describes a pigment-containing basecoating composition ofthe present invention which contains a polysiloxane borate as anadhension promoter. The basecoating composition was prepared in threestages as described above with reference to the basecoating compositionof Comparative Example 24. Pigment Additive Solution Resin Solids SolidsSolids Weight (grams) (grams) (grams) (grams) Organic PortionN-Butoxypropanol 0 0 0 45.04 Cymel 303LF 25 0 0 25 Cymel 385 5 0 0 6.25TINUVIN ®1130 0 0 1.4 1.40 Aqua Paste 3620-D23 1.5 15.1 0 23.50 AquaPaste 3700-A23 0.4 4.3 0 6.50 Phosphatized Epoxy 0 0 0.24 0.39 AqueousPortion SHELLSOL ® 071 0 0 0 6 Latex of Example 24 58.1 0 0 140Deionized water 0 0 0 50 Acrylic Grind 6 0 0 23.1 Dispersion of Example24 50% DMEA solution 0 0 0 2.2 Thickener Solution Deionized water 0 0 010 50% DMEA Solution 0.0 0.0 0.0 2.5 Oligomeric Polyester 4 0.0 0.0 5 ofExample24 Adhesion promoter Polysiloxane borate of 0 0 .5 .9 Example I

The polysiloxane borate of Example I was post-added under agitation tothe basecoating composition of Example 25 in the amounts indicatedabove.

Testing

Each of the basecoating compositions of Comparative Example 24 andExample 25 was applied on ED5000 panels primed with GPXH5379 using theSames 402 gun mounted on the Kohne machine in a one-coat application.The basecoats were given a five minute ambient flash and then pre-bakedat the various conditions listed in the following Table 7. Basecoat filmbuild was targeted at 0.5 to 0.7 mils. A two-componentisocyanate-containing clearcoat, TKU-1050AR (available from PPGIndustries, Inc.) was applied under the same conditions as was thebasecoat, except the clearcoating composition was applied in two coats.The panels thus prepared were given a ten minute ambient flash periodbefore curing for 30 minutes at 250° F. (121° C.). The cured clearcoatdry film thickness ranged from 1.8-2.0 mils (45.7 to 50 micrometers).

Note, a 5 minute at 200° F. (93° C.) prebake is the standard prebakecondition. The 10 minute prebake at 250° F. (121° C.) prebake which wasused in the above described evaluations was intended to simulate an overpre-bake condition (as would be encountered on a commercial coating lineshould there be a malfunction in the prebake oven).

A 30 minute prebake at 250° F. (121° C.)/5 minute prebake at 200° F.(93° C.) was used to simulate a malfunction in the clearcoat booth oroven. In this instance, the basecoat is applied and given a standardprebake but no clearcoat is applied due to a malfunction on theclearcoating line. Thus the basecoat receives a full clearcoat bake of30 minutes at 250° F. (121° C.). As mentioned above, in such situations,some automobile manufacturers elect to reapply the basecoat and give ita standard prebake before clearcoating.

Adhesion was tested 1 hour after clearcoating using a razor knife to cuta 6×6 two-millimeter grid through the total paint coating and thentaping with black Tesa tape. The adhesion is rated according to ASTM D3359-97 which assigns a whole number from 5(no adhesion loss) to 0(totaladhesion loss). In this case an acceptable adhesion rating is a 5 or a4. For the 10 minutes at 250° F. prebake scenario described above, theadhesion between clearcoat and basecoat was evaluated. For the 30minutes at 250° F. (121° C.)/5 minutes at 250° F. (121° C.) prebakescenario described above, the adhesion between the basecoat layers wasevaluated. Adhesion test results are presented below in the followingTable 7. TABLE 7 Elemental CROSS HATCH BASECOATING Weight % on PREBAKEADHESION COMPOSITION Resin Solids SCENARIO RATING EXAMPLE 24* 0 5′ at200 F. 5 (standard) EXAMPLE 25 0.01 5′ at 200 F. 5 (standard) EXAMPLE24* 0 10′ at 250 F. 0 EXAMPLE 25 0.01 10′ at 250 F. 5 EXAMPLE 24* 0 30′at 250 F./ 0 5′ at 200 F. EXAMPLE 25 0.01 30′ at 250 F./ 5 5′ at 200 F.

The data presented above in Table 7 illustrates that the basecoatingcomposition of Comparative Example 24 does not exhibit acceptableclearcoat-to-basecoat adhesion when the basecoat undergoes an extendedprebake (10′ at 250° F. (121° C.) prebake). Nor does this basecoatexhibit acceptable basecoat-to-basecoat adhesion when the basecoat isfully baked and then another layer of basecoat is applied and given thestandard prebake (30′ at 250° F. (121° C.)/5′ at 200° F. (93° C.)prebake) before clearcoating. By contrast, the basecoating compositionsof the present invention comprising the polysiloxane borate as anadhesion promoter exhibits excellent adhesion in both prebake scenarios.

CARBAMATE-CONTAINING CLEARCOAT COMPOSITIONS Comparative Example 26

This comparative example describes the preparation of thermosettingclearcoating composition which does not contain an adhesion promoter.The clearcoating composition was prepared by mixing together thefollowing ingredients sequentially: Solid Solution Ingredient Weight (g)Weight. (g) Xylene 5.75 Aromatic 100 12.00 Hexyl cellosolve 2.57 MethylEthyl Ketone 11.7 Tinuvin 328¹ 1.29 1.29 Tinuvin 900² 1.29 1.29 AcrylicMicrogel Dispersion³ 1.74 5.79 Silica Dispersion⁴ 9.17 21.3 RESIMENE757⁵ 38.13 39.3 Ethanol 4.45 Carbamate functional 39.5 54.9 Polyester ofExample CC Carbamate Functional 13.17 20.9 Acrylic of Example BB Tinuvin292⁶ 0.32 0.32 DISPARLON OX-60⁷ 0.06 0.12 Flow Additive⁸ 0.38 0.63Catalyst⁹ 1.03 1.47¹Substituted benzotriazole UV Light stabilizer available from Ciba GeigyCorporation.²Substituted benzotriazole UV Light stabilizer available from Ciba GeigyCorporation.³A non-aqueous dispersion of an acrylic polymer formed fromethyleneglycol dimethacrylate, styrene, butyl acrylate and methylmethacrylate.⁴Fumed silica grind.⁵A fully alkylated methoxy/butoxy functional aminoplast available fromSolutia, Inc.⁶Sterically hindered amine light stabilizer available from Ciba GeigyCorporation.⁷Additive from King Industries.⁸Additive from DuPont.⁹Dodecyl benzene sulfonic acid solution.

Example 27

This example describes the preparation of a clearcoating composition ofthe present invention which contains a boric acid ester as an adhesionpromoter. The clearcoatng composition was prepared by mixing togetherthe following ingredients: Solid Solution Ingredients Weight. (g)Weight. (g) Clearcoating Composition of 106.08 184.9 Example 26 BoricAcid Ester of Example J 1.0 1.4

Example 28

This example describes the preparation of a clearcoating composition ofthe present invention which contains a boric acid ester as an adhesionpromoter. The clearcoating composition was prepared by mixing togetherthe following ingredients: Solid Solution Ingredients Weight. (g)Weight. (g) Clearcoating Composition of 106.08 184.9 Example 26Polysiloxane polyol of Example AA 1.0 1.0 Boric Acid Ester of Example F0.56 0.90

Example 29

This example describes the preparation of a clearcoating composition ofthe present invention which contains a boric acid ester as an adhesionpromoter. The clearcoating composition was prepared by mixing togetherthe following ingredients: Solid Solution Ingredients Weight. (g)Weight. (g) Clearcoating composition of 106.08 184.5 Example 26 BoricAcid Ester of Example F 0.56 0.90

Comparative Example 30

This comparative example describes the preparation of a clearcoatingwhich contains a polysiloxane polyol, but no adhesion promoter. Theclearcoating composition was prepared by mixing together the followingingredients: Solid Solution Ingredients Weight (g) Weight (g)Clearcoating composition of 106.08 184.5 Example 26 Polysiloxane polyolof Example AA 0.88 0.88Testing

The film-forming compositions of Examples 26-30 were applied topigmented basecoats to form color-plus-clear composite coatings over asteel substrate previously coated with an electrocoat primer and aprimer surfacer. The basecoat used for the examples is commerciallyavailable from PPG Industries, Inc. and is identified as ODCT6505(silver metallic). The primer used is commercially available from PPGIndustries, Inc. and is identified as FCP-6759. The electrocoat used onthe steel is commercially available from PPG Industries, Inc. and isidentified as ED5000.

The basecoat was spray applied in two coats to the primed electrocoatedsteel panels at a temperature of about 75° F. (24° C.). A 60 secondsflash time was allowed between the two basecoat applications. After thesecond basecoat application, a 90 seconds flash time was allowed atabout 75° F. (24° C.) before the application of the clear coatingcomposition. The clear coating compositions of Examples 26-30 were eachapplied to a basecoated panel in two coats with a 60 seconds flash at75° F. (24° C.) allowed between coats. The composite coating was allowedto air flash at about 75° F. (24° C.) for 8-10 minutes before baking at285° F. (141° C.) to cure both the basecoat and the clearcoat. Thepanels were baked in a horizontal position. The colored panel for eachclearcoat example was baked for 30 minutes and used to test foradhesion.

In order to test the adhesion of the clearcoat to the windshieldadhesive, a bead of windshield adhesive was applied to the clearcoatsurface within 1-4 hours following the 30 minutes at 285° F. (141° C.)bake. The windshield adhesive used for Examples 26-30 is commerciallyavailable from Essex Speciality Products Company and is identified asAdhesive 15625.

A 5 mm×5 mm×250 mm adhesive bead was placed on the clearcoat surface ofthe cured color-plus-clear composite. The adhesive plus thecolor-plus-clear composite was cured for 72 hours at about 75° F. (24°C.) and 20-50% relative humidity. The cured adhesive bead was cut with arazor blade. A cut was made through the adhesive bead at a 60° angle at12 mm intervals while pulling back the edge of the adhesive at a 180°angle. A minimum of 10 cuts was done for each system. The desired resultis described as 100% cohesive failure (CF). Cohesive failure (CF) occurswhen the integrity of the adhesive bead is lost as a result of cuttingand pulling rather than the bond between the adhesive bead and theclearcoat surface. The adhesion results over the silver metallicbasecoat are summarized in Table 8 below. TABLE 8 CLEARCOATING PercentCohesive Failure COMPOSITION (% CF) Example 26* 0% CF Example 27 100% CFExample 28 100% CF Example 29* 0% CF Example 30* 0% CF*Comparative Examples

The data presented above in Table 8 illustrate that in the absence ofthe siloxane plus borate combination (Comparative Examples 26, 29 and30) the adhesive beads do not adhere to the clearcoat surface indicating0% cohesive failure. By contrast, clearcoats containing a siloxane plusborate additive (Examples 27 and 28) adhere strongly to the adhesivebeads (100% cohesive failure) and the mode of failure occurs within theadhesive bead itself.

POWDER COATING COMPOSITIONS Examples 31 through 33

Each epoxy-acid powder clearcoat composition in Examples 31 through 33in Table 9 below is shown in parts by weight. Each composition wasprocessed in the following manner. The components were blended in aHenschel Mixer for 60 to 90 seconds. The mixtures were then extrudedthrough a Werner & Pfleider co-rotating twin screw extruder operating ata screw speed of 450 RPM with barrel temperatures adjusted to produceextrudate at a temperature of 100° C. to 125° C. The extruded materialwas then ground to a mean particle size of 17 to 27 microns using an ACM2 (Air Classifying Mill from Hosakowa Micron Powder Systems). Thefinished powders were electrostatically sprayed onto test panels andevaluated for coatings properties. TABLE 9 Example 31 ComponentComparative Example 32 Example 33 ¹GMA Acrylic 69.99 69.80 67.57Dodecanedioic Acid 20.91 20.85 20.18 ²Flow Additive 1.00 1.00 0.97Benzoin 0.20 0.20 0.19 ³Wax C Micropowder 0.60 0.60 0.58 ⁴Tinuvin 1442.00 2.00 1.94 ⁵CGL1545 2.00 2.00 1.94 ⁶HCA-1 2.00 2.00 1.94 ⁷Armeen M2C1.00 1.00 0.97 ⁸Aluminum Oxide 0.30 0.30 0.29 ⁹Orthoboric Acid 0.00 0.250.00 Siloxane Borate 0.00 0.00 3.55 of Example I¹Proprietary Acrylic²Proprietary Flow Additive³Wax C Micropowder, a fatty acid amide (ethylene bis-stearolyamide),commercially available from Hoechst-Celanese.⁴2-tert-butyl-2-(4-hydroxy-3,5-di-tert-butylbenzyl)[bis(methyl-2,2,6,6,-tetramethyl-4-piperidinyl)]dipropionate),an ultraviolet light stabilizer commercially available from Ciba-GeigyCorp.⁵2-[4((2-Hydroxy-3-(2-ethylhexyloxy)propyl)-oxy]-2-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine),an ultraviolet light stabilizer commercially available form Ciba-GeigyCorp.⁶HCA-1, an anti-yellowing agent commercially available from SankoChemical Corp.⁷Methyl dicocoamine commercially available from Akzo-Nobel Corp.⁸Microgrit WCA3 commercially available from Micro Abrasives.⁹Optibor TP, commercially available from U.S. Borax, Inc.

Each of the powder coating compositions of Examples 31 to 33 wasprepared for testing in the following manner. The test panels,pre-coated with an electrocoat primer commercially available from PPGIndustries, Inc., as ED5000 were coated with a primer/surfacer and abasecoat by spray application to a film thickness of 1.1 mils (27.9microns) and 0.6 mils (15.2 microns) respectively, with graysolventborne primer commercially available form Akzo-Nobel Corp., and awaterborne silver basecoat (prepared by blending under agitation: 171.6g SHELLSOL®071, 1700.4 g resin (dispersion prepared from 60% acrylicgrafted to 40% poylurethane), 902.2 g DOATAN 6462 available fromSolutia, 559 g Hexyl Cellosolve®, 31.2 g dimethylethanolamine 50%solution, 2876.9 g deionized water, 102.7 g octanol, 37.7 gTinuvin®1130, 13 g phosphatized epoxy (prepared from EPON®828, apolyglicydyl ether of Bisphenol A, available form Shell Oil and ChemicalCo., reacted with phosphoric acid at an 83:17 weight ratio.), 260 gCymel®303LF melamine available from Cytec Industries, Inc., 365.3 g TOYO7106 NS untreated aluminum available from Toyo Aluminum K. K. and 107.9g aluminum passivator prepared according to U.S. Pat. 5,429,674 Example6.). The basecoat panels were then flashed 10 minutes at 176° F. (80°C.) before electrostatically applying the powder clearcoatingcompositions of Examples 31 to 33. The powder coatings were applied at1.97-2.36 mils (50-60 microns) film thickness and cured for 30 minutesat 293° F. (145° C.). Test panels were then given a second layer of thewaterborne silver basecoat. Finally, a two component isocyanateclearcoat commercially available from BASF, was applied at a filmthickness of 1.6 to 1.8 mils (40.6 to 45.7 microns) and cured for 20minutes at 293° F. (145° C.). The test panels coated with the powderclearcoats from Examples 31 to 33 were then evaluated for adhesion bythe following procedure:

A cutting template, Super Cutter Guide manufactured by Taiyu Kizai Coltd, was used along with a blade to scribe a grid into the test panels.The lines of the grid are spaced 3 mm apart. Black tape available asTesa 4651 through Beiersdorf AG is then placed across the grid andrubbed to insure good surface contact. The tape is then yanked off. Thepanels are then rated according to the percentage of surface area of thegrid that was pulled off the grid as % failure.

Results are reported in Table 10 below. TABLE 10 Coating Composition %Failure Comparative Example 31 100% complete delamination Example 32 35%partial delamination Example 33 8% slight delamination

The data presented above in Table 10 illustrate that the powderclearcoating compositions of the present invention (Examples 32 and 33)provide improved adhesion over that of the Comparative Example 31 whichcontains no boron-containing compound.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications which are within the spirit and scopeof the invention, as defined by the appended claims.

1. In a multi-layer composite of two or more polymeric layers at leastone of which is formed from a thermosetting composition, said compositecomprising at least a first polymeric layer formed on a substrate and asecond polymeric layer over at least a portion of said first polymericlayer, wherein in the absence of a boron-containing compound, said firstpolymeric layer and said second polymeric layer have poor interlayeradhesion, the improvement comprising the inclusion of at least oneboron-containing compound selected from boric acid, boric acidequivalents, and mixtures thereof in one or both of said first andsecond polymeric layers in an amount sufficient to improve theinterlayer adhesion of said first polymeric layer and said secondpolymeric layer, wherein the concentration of, wherein the concentrationof the boron-containing compound at a surface region of a polymericlayer containing the boron-containing compound is greater than theconcentration of the boron-containing compound in the bulk region of thepolymeric layer.
 2. The composite of claim 1, wherein at least oneboron-containing compound is present in said first polymeric layer. 3.The composite of claim 1, wherein at least one boron-containing compoundis present in said second polymeric layer.
 4. The composite of claim 1,wherein at least one boron-containing compound is present in said firstpolymeric layer and in said second polymeric layer.
 5. The composite ofclaim 1, wherein said boron-containing compound is selected from atleast one of boric acid, boric acid ester, metal borate, derivativesthereof and mixtures thereof.
 6. The composite of claim 5, wherein saidboron-containing compound comprises boric acid.
 7. The composite ofclaim 5, wherein said boron-containing compound comprises a boric acidester selected from at least one of triisopropyl borate, trimethylborate, triphenyl borate, trimethoxyboroxine, polysiloxane borate,acrylic borate, and mixtures thereof.
 8. In a multi-layer composite oftwo or more polymeric layers, at least one of which is formed from athermosetting composition, said composite comprising at least a firstpolymeric layer formed on a substrate and a second polymeric layerformed over at least a portion of said first polymeric layer, wherein inthe absence of a boron-containing compound, said first polymeric layerand said second polymeric layer have poor interlayer adhesion, theimprovement comprising the inclusion of at least one boron-containingcompound in one or both of said first and second polymeric layers in anamount sufficient to improve the interlayer adhesion of said firstpolymeric layer and said second polymeric layer, wherein saidboron-containing compound comprises a boric acid ester derivativeselected from at least one of triethanolamineborate, mannitol borate,n-propanol amine borate, trimethylolpropane borate, glycerol borate, andmixtures thereof.
 9. The composite of claim 1, wherein both the firstpolymeric layer and the second polymeric layer are formed fromthermosetting compositions.
 10. In a mulit-layer composite of two ormore polymeric layers, at least one of which is formed from athermosetting composition, said composite comprising at least a firstpolymeric layer formed on a substrate and a second polymeric layerformed over at least a portion of said first polymeric layer, wherein inthe absence of a boron-containing compound, said first polymeric layerand said second polymeric layer have poor interlayer adhesion, theimprovement comprising the inclusion of at least one boron-containingcompound in one or both of said first and second polymeric layers in anamount sufficient to improve the interlayer adhesion of said firstpolymeric layer and said second polymeric layer, wherein saidboron-containing compound comprises the reaction product formed from thefollowing reactants: (A) at least one polysiloxane comprising at leastone of the following structural units (I):R¹ _(n)R² _(m)SiO_((4-n-m)/2)  (I) wherein each R¹, which may beidentical or different, represents H, OH, a monovalent hydrocarbon groupor a monovalent siloxane group; each R², which may be identical ordifferent, represents a group comprising one or more active hydrogens;and m and n each represent a positive number fulfilling the requirementsof 0<m<4; 0<n<4; and 2≦(m+n)<4; and (B) a boron-containing compoundselected from at least one of boric acid, boric acid equivalents, andmixtures thereof.
 11. The composite of claim 10, wherein at least one R²comprises OR′, where R′ is H or an alkyl group havin 1 to 20 carbonatoms.
 12. The composite of claim 10, wherein said polysiloxanecomprises one or more ungelled non-hydrolyzable organic polysiloxaneshaving reactive functional groups, said polysiloxane having thefollowing structure (II) or (III):

wherein: m has a value of at least 1; m′ ranges from 0 to 75; n rangesfrom 0 to 75; n′ ranges from 0 to 75; each R, which may be identical ordifferent, is selected from H, OH, monovalent hydrocarbon groups,monovalent siloxane groups, and mixtures of any of the foregoing; andR^(a) comprises the following structure (IV):—R³—X  (IV) wherein —R³ is selected from an alkylene group, anoxyalkylene group, an alkylene aryl group, an alkenylene group, anoxyalkenylene group, and an alkenylene aryl group; and; and R^(a)comprises the following structure (IV):R³—X  (IV) wherein R³ is alkenylene, alkylene, oxyalkylene, alkylenearyl or alkenylene; and X represents a group which comprises at leastone reactive functional group selected from at least one of a hydroxylgroup, a carboxyl group, a primary amine group, a secondary amine group,an amide group, a carbamate group, a urea group, an anhydride group, ahydroxy alkylamide group, and an epoxy group.
 13. The composite of claim12, wherein the polysiloxane is the reaction product of the followingreactants: (A) at least one silicon hydride-containing polysiloxanehaving the following structure (V):

wherein the R groups are selected from H, OH, monovalent hydrocarbongroups, siloxane groups and mixtures thereof, wherein at least one ofthe groups represented by R is H, and n′ ranges from 0 to 100, such thatthe mole percent of hydrogen-bonded silicon atoms to non-hydrogen-bondedsilicon atoms ranges from 10 to 100 percent; and (B) one or morehydroxyl functional materials comprising at least one primary hydroxylgroup and at least one unsaturated bond capable of undergoinghydrosilylation reaction.
 14. The composite of claim 13, whereinreactant (B) is a hydroxyl functional group-containing allyl etherselected from trimethylolpropane monoallyl ether, pentaerythritolmonoallyl ether, trimethylolpropane diallyl ether and mixtures thereof;or an allyl alcohol.
 15. The composite of claim 10, wherein the firstpolymeric layer is formed from a thermosetting composition comprising aboron-containing compound present in said thermosetting composition inan amount sufficient to provide an amount of boron ranging from 0.001 to5 percent by weight, based on weight of total resin solids present inthe thermosetting composition.
 16. The composite of claim 1, wherein oneor both of said first polymeric layer and said second polymeric layercomprises a cured layer formed from a thermosetting compositioncomprising: (A) at least one film-forming polymer having reactivefunctional groups; (B) at least one curing agent having functionalgroups reactive with the functional groups of (A); and (C) at least oneboron-containing compound selected from at least one of boric acid,boric acid equivalents, and mixtures thereof.
 17. The composite of claim16, wherein the film-forming polymer (A) comprises at least one polymerselected from an acrylic polymer, a polyester polymer, a polyurethanepolymer, a polyether polymer, a silicon-based polymer, and mixturesthereof.
 18. The composite of claim 16, wherein the film-forming polymer(A) comprises an acrylic polymer, a polyester polymer, and mixturesthereof.
 19. The composite of claim 16, wherein the film-forming polymer(A) comprises an acrylic polymer.
 20. The composite of claim 16, whereinthe film-forming polymer (A) comprises functional groups selected from ahydroxyl group, a carboxyl group, an isocyanate group, a blockedpolyisocyanate group, a primary amine group, a secondary amine group, anamide group, a carbamate group, a urea group, a urethane group, a vinylgroup, an unsaturated ester group, a maleimide group, a fumarate group,an anhydride group, a hydroxy alkylamide group, and an epoxy group. 21.The composite of claim 16, wherein the film-forming polymer comprisesfunctional groups selected from hydroxyl groups, carbamate groups andmixtures thereof.
 22. The composite of claim 19, wherein thefilm-forming polymer (A) comprises the residue of a beta-hydroxygroup-containing monomer selected from at least one of (A) the reactionproduct of an ethylenically unsaturated acid functional monomer and anepoxy functional compound having no ethylenic unsaturation; and (B) thereaction product of an ethylenically unsaturated, epoxy functionalmonomer and a saturated carboxylic acid.
 23. The composite of claim 16,wherein the curing agent (B) comprises aminoplast resins,polyisocyanates, blocked polyisocyanates, polycarboxylic acids,polyanhydrides, polyepoxides, polyamines, polyols, and mixtures thereof.24. The composite of claim 8, wherein one or both of said firstpolymeric layer and said second polymeric layer comprises a cured layerformed from a thermosetting composition comprising: (A) at least onefilm-forming polymer having reactive functional groups selected fromhydroxyl groups, carbamate groups and mixtures thereof; (B) at least onecuring agent having functional groups reactive with the functionalgroups of (A) selected from aminoplast resins, polyisocyanates, blockedisocyanates and mixtures thereof; and (C) at least one boron-containingcompound selected from one or more of triethanolamineborate, mannitolborate, n-propanol amine borate, trimethylolpropane borate, glycerolborate, and mixtures thereof.
 25. The composite of claim 4, wherein theat least one acrylic film-forming polymer having reactive functionalgroups (A), comprises the residue of a beta-hydroxy group-containingmonomer selected from at least one of: (i) the reaction product of anethylenically unsaturated acid functional monomer and an epoxyfunctional compound having no ethylenic unsaturation; and (ii) thereaction product of an ethylenically unsaturated, epoxy functionalmonomer and a saturated carboxylic.
 26. The composite of claim 25,wherein the at least one curing agent (B) having functional groupsreactive with the functional groups of (A) comprises at least oneaminoplast resin and at least one blocked isocyanate compound comprisinga tricarbamoyl triazine compound.
 27. The composite of claim 16, whereinboth the first polymeric layer and the second polymeric layer are formedfrom a thermosetting composition.
 28. The composite of claim 27, whereinthe first polymeric layer is formed from a thermosetting compositioncomprising: (A) at least one film-forming polymer having reactivefunctional groups; (B) at least one curing agent having functionalgroups reactive with the functional groups of (A); and (C) at least oneboron-containing compound selected from boric acid, boric acidequivalents, and mixtures thereof.
 29. The composite of claim 27,wherein the first polymeric layer is formed from a thermosettingcomposition comprising: (A) at least one film-forming acrylic polymercomprising functional groups selected from hydroxyl groups, carbamategroups and mixtures thereof; (B) at least one curing agent selected fromaminoplast resins, polyisocyanates, blocked polyisocyanates and mixturesthereof; and (C) at least one boron-containing compound selected fromboric acid, boric acid equivalents, and mixtures thereof.
 30. Thecomposite of claim 27, wherein the boron-containing compound (C) ispresent in the thermosetting composition in an amount sufficient toprovide an amount of boron ranging from 0.001 to 5 percent by weightbased on total resin solids present in the thermosetting composition.31. The composite of claim 8, wherein said first polymeric layer isformed from a cured layer formed from a thermosetting compositioncomprising: (A) at least one film-forming acrylic polymer comprisingfunctional groups selected from hydroxyl groups, carbamate groups andmixtures thereof; (B) at least one curing agent having functional groupsreactive with the functional groups of (A) comprising an aminoplastresin, and a blocked isocyanate comprising a tricarbamoyl triazinecompound; and (C) at least one boron-containing compound selected fromboric acid esters selected from one or more of triethanolamineborate,mannitol borate, n-propanol amine borate, trimethylolpropane borate,glycerol borate, and mixtures thereof; and said second polymeric layercomprises a cured layer formed from a thermosetting compositioncomprising: (D) at least one film-forming polymer having reactivefunctional groups; (E) at least one curing agent selected fromaminoplast resins, polyisocyanates, blocked polyisocyanates and mixturesthereof; and (F) at least one boron-containing compound selected fromboric acid esters selected from one or more of triethanolamineborate,mannitol borate, n-propanol amine borate, trimethylolpropane borate,glycerol borate, and mixtures thereof.
 32. The composite of claim 10,wherein both of said first polymeric layer and said second polymericlayer are cured layers formed from a thermosetting compositioncomprising: (A) at least one film-forming polymer having reactivefunctional groups; (B) at least one curing agent having functionalgroups reactive with the functional groups of (A); and (C) at least oneboron-containing compound selected from reaction products formed fromthe following reactants: (i) at least one polysiloxane comprising atleast one of the following structural units (I):R¹ _(n)R² _(m)SiO_((4-n-m)/2)  (I) wherein each R′ is independentlyselected from H, a monovalent hydrocarbon group or a siloxane group;each R² independently is a group comprising OR′, where R′ is H or analkyl group having 1 to 20 carbon atoms; and m and n each represent apositive number fulfilling the requirements of 0<m<4; 0<n<4; and2≦(m+n)<4; and (ii) a boron-containing compound comprising at least oneof boric acid, boric acid equivalents, and mixtures thereof.
 33. Thecomposite of claim 32, wherein the boron-containing compound (C)comprises boric acid and/or boric acid ester.
 34. The composite of claim32, wherein the boron-containing compound (C) is present in thethermosetting composition in an amount sufficient to provide an amountof boron ranging from 0.001 to 5 weight percent based on weight of totalresin solids present in the thermosetting composition.
 35. The compositeof claim 27, wherein said first thermosetting composition comprises abase coating composition and second thermosetting composition comprisesa top coating composition.
 36. The composite of claim 35, wherein saidfirst thermosetting composition comprises a substantially pigment-freebase coating composition, and said second thermosetting compositioncomprises a substantially pigment-free top coating composition.
 37. Thecomposite of claim 35, wherein said first thermosetting compositioncomprises a pigment-containing base coating composition, and said secondthermosetting composition comprises a pigment-containing top coatingcomposition.
 38. The composite of claim 35, wherein said firstthermosetting composition comprises a pigment-containing base coatingcomposition, and said second thermosetting composition comprises asubstantially pigment-free coating composition.
 39. The composite ofclaim 35, wherein said first thermosetting composition comprises asubstantially pigment-free base coating composition, and said secondthermosetting composition comprises a pigment-containing top coatingcomposition.
 40. The composite of claim 36, wherein said secondthermosetting composition comprises an adhesive composition.
 41. Thecomposite of claim 1, wherein said first polymeric layer is formed on ametallic substrate.
 42. The composite of claim 1, wherein said firstpolymeric layer is formed on an elastomeric substrate.
 43. The compositeof claim 1, wherein said first polymeric layer is formed on a substratecomprising a substrate and one or more polymeric layers.
 44. Thecomposite of claim 43, wherein said substrate comprises a substrate andone or more polymeric layers formed from one or more thermosettingfilm-forming compositions.
 45. In a curable coating composition used toform a multi-layer composite coating comprising two or more curedcoating layers, said multi-layer composite coating comprising at least afirst coating layer formed on a substrate and a second coating layerover at least a portion of said first polymeric layer, wherein one orboth of said first coating layer and said second coating layer areformed from said curable coating composition, and wherein in the absenceof a boron-containing compound, said first coating layer and said secondcoating layer have poor interlayer adhesion, the improvement comprisingthe inclusion in said curable coating composition of a boron-containingcompound selected from at least one of boric acid, boric acidequivalents, and mixtures thereof in an amount sufficient to improve theinterlayer adhesion between said first coating layer and said secondcoating layer, wherein the concentration of the boron-containingcompound at a surface region of a coating layer containing theboron-containing compound is greater than the concentration of theboron-containing compound in the bulk region of the coating layer. 46.The coating composition of claim 45, wherein at least oneboron-containing compound is present in said first coating layer. 47.The coating composition of claim 45, wherein at least oneboron-containing compound is present in said second coating layer. 48.The coating composition of claim 45, wherein at least oneboron-containing compound is present in said first coating layer and insaid second coating layer.
 49. The coating composition of claim 45,wherein said boron-containing compound is selected from at least one ofboric acid and boric acid ester.
 50. The coating composition of claim45, wherein both the first coating layer and the second coating layerare formed from curable coating compositions.
 51. In a curable coatingcomposition used to form a multi-layer composite coating comprising twoor more cured coating layers, said multi-layer composite coatingcomprising at least a first coating layer formed on a substrate and asecond coating layer over at least a portion of said first polymericlayer, wherein one or both of said first coating layer and said secondcoating layer are formed from said curable coating composition, andwherein in the absence of a boron-containing compound, said firstcoating layer and said second coating layer have poor interlayeradhesion, the improvement comprising the inclusion in said curablecoating composition of a boron-containing compound selected from atleast one of boric acid, boric acid equivalents, and mixtures thereof inan amount sufficient to improve the interlayer adhesion between saidfirst coating layer and said second coating layer, wherein saidboron-containing compound comprises the reaction product of thefollowing reactants: (A) at least one polysiloxane comprising at leastone of the following structural units (I):R¹ _(n)R² _(m)SiO_((4-n-m)/2)  (I) wherein each R¹, which may beidentical or different, represents H, OH, a monovalent hydrocarbon groupor a monovalent siloxane group; each R², which may be identical ordifferent, represents a group comprising one or more active hydrogens;and m and n each represent a positive number fulfilling the requirementsof 0<m<4; 0<n<4; and 2≦(m+n)<4; and (B) at least one boron-containingcompound selected from at least one of boric acid, boric acidequivalents, and mixtures thereof.
 52. The coating composition of claim51, wherein at least one R² comprises OR′, where R′ represents H or analkyl group having 1 to 20 carbon atoms.
 53. The coating composition ofclaim 51, wherein said polysiloxane (A) comprises one or more ungelled,organic polysiloxanes having reactive functional groups, saidpolysiloxane having the following structure (II) or (III):

where m has a value of at least 1; m′ ranges from 0 to 75; n ranges from0 to 75; n′ ranges from 0 to 75; each R, which may be identical ordifferent, is selected from H, OH, monovalent hydrocarbon groups,monovalent siloxane groups, and mixtures of any of the foregoing; andR^(a) comprises the following structure (IV):—R³—X  (IV) wherein —R³ is selected from an alkylene group, anoxyalkylene group, an alkylene aryl group, an alkenylene group, anoxyalkenylene group, and an alkenylene aryl group; and X represents agroup which comprises at least one reactive functional group selectedfrom selected from at least one of a hydroxyl group, a carboxyl group, aprimary amine group, a secondary amine group, an amide group, acarbamate group, a urea group, an anhydride group, a hydroxy alkylamidegroup, and an epoxy group.
 54. The coating composition of claim 53,wherein the polysiloxane comprises the reaction product of the followingreactants: (A) at least one silicon hydride-containing polysiloxanehaving the following structure (V):

wherein the R groups are selected from H, OH, monovalent hydrocarbongroups, siloxane groups and mixtures thereof, wherein at least one ofthe groups represented by R is H, and n′ ranges from 0 to 100, such thatthe mole percent of hydrogen-bonded silicon atoms to non-hydrogen-bondedsilicon atoms ranges from 10 to 100 percent; and (B) one or morehydroxyl functional materials comprising at least one hydroxyl group andat least one unsaturated bond capable of undergoing hydrosilylationreaction.
 55. The coating composition of claim 54, wherein reactant (B)comprises at least one of an allyl alcohol, and a hydroxyl functionalgroup-containing allyl ether selected format least one oftrimethylolpropane monoallyl ether, pentaerythritol monoallyl ether,trimethylolpropane diallyl ether and mixtures thereof.
 56. The coatingcomposition of claim 45, comprising a boron-containing compound presentin an amount sufficient to provide an amount of boron in at least one ofsaid cured coating layers ranging from 0.001 to 5 percent by weight,based on the weight of total resin solids present in said curablecoating composition.
 57. The coating composition of claim 45, whereinone or both of said first coating layer and said second coating layercomprises a cured coating layer formed from a curable coatingcomposition comprising: (A) at least one film-forming polymer havingreactive functional groups; (B) at least one curing agent havingfunctional groups reactive with the functional groups of (A); and (C) atleast one boron-containing compound selected from at least one of boricacid, boric acid equivalents, and mixtures thereof.
 58. The coatingcomposition of claim 57, wherein the film-forming polymer (A) comprisesa polymer selected from an acrylic polymer, a polyester polymer, apolyurethane polymer, a polyether polymers a silicon-based polymer, andmixtures thereof.
 59. The coating composition of claim 57, wherein thefilm-forming polymer comprises an acrylic polymer, a polyester polymerand mixtures thereof.
 60. The coating composition of claim 57 whereinthe film-forming polymer comprises an acrylic polymer.
 61. The coatingcomposition of claim 57, wherein the film-forming polymer comprisesfunctional groups selected from a hydroxyl group, a carboxyl group, anisocyanate group, a blocked isocyanate group, a primary amine group, asecondary amine group, an amide group, a carbamate group, a urea group,a urethane group, a vinyl group, an unsaturated ester group, a maleimidegroup, a fumarate group, an anhydride group, a hydroxy alkylamide group,and an epoxy group.
 62. The coating composition of claim 57, wherein thefilm-forming polymer comprises functional groups selected from hydroxylgroups, carbamate groups and mixtures thereof.
 63. The coatingcomposition of claim 60, wherein the film-forming polymer (A) comprisesthe residue of a beta-hydroxy group-containing monomer selected from atleast one of (A) the reaction product of an ethylenically unsaturatedacid functional monomer and an epoxy functional compound having noethylenic unsaturation; and (B) the reaction product of an ethylenicallyunsaturated, epoxy functional monomer and a saturated carboxylic acid.64. The coating composition of claim 57, wherein the curing agent (B)comprises aminoplast resins, polyisocyanates, blocked isocyanates,polycarboxylic acids, polyanhydrides, polyepoxides, polyamines, polyols,and mixtures thereof.
 65. In a curable coating composition used to forma multi-layer composite coating comprising two or more cured coatinglayers, said multi-layer composite coating comprising at least a firstcoating layer formed on a substrate and a second coating layer over atleast a portion of said first polymeric layer, —wherein one or both ofsaid first coating layer and said second coating layer are formed fromsaid curable coating composition, and wherein in the absence of aboron-containing compound, said first coating layer and said secondcoating layer have poor interlayer adhesion, the improvement comprisingthe inclusion in said curable coating composition of a boron-containingcompound selected from at least one of boric acid, boric acidequivalents, and mixtures thereof in an amount sufficient to improve theinterlayer adhesion between said first coating layer and said secondcoating layer, wherein one or both of said first coating layer and saidsecond coating layer comprises a cured coating layer formed from acurable coating composition comprising: (A) at least one film-formingpolymer having reactive functional groups selected from hydroxyl groups,carbamate groups and mixtures thereof; (B) at least one curing agenthaving functional groups reactive with the functional groups of (A)selected from aminoplast resins, polyisocyanates, blockedpolyisocyanates and mixtures thereof; and (C) at least oneboron-containing compound selected from at least one of boric acid,boric acid equivalents, and mixtures thereof.
 66. In a curable coatingcomposition used to form a multi-layer composite coating comprising twoor more cured coating layers, said multi-layer composite coatingcomprising at least a first coating layer formed on a substrate and asecond coating layer over at least a portion of said first polymericlayer, wherein one or both of said first coating layer and said secondcoating layer are formed from said curable coating composition, andwherein in the absence of a boron-containing compound, said firstcoating layer and said second coating layer have poor interlayeradhesion, the improvement comprising the inclusion in said curablecoating composition of a boron-containing compound selected from atleast one of boric acid, boric acid equivalents, and mixtures thereof inan amount sufficient to improve the interlayer adhesion between saidfirst coating layer and said second coating layer, wherein one or bothof said first coating layer and said second coating layer comprises acured coating layer formed from a curable coating compositioncomprising: (A) at least one acrylic film-forming polymer havingreactive functional groups selected from hydroxyl groups, carbamategroups and mixtures thereof, the acrylic film-forming polymer comprisingresidues of a beta-hydroxy group containing monomer selected from atleast one of: (i) the reaction product of an ethylenically unsaturatedacid functional monomer and an epoxy functional compound having noethylenic unsaturation; and (ii) the reaction product of anethylenically unsaturated, epoxy functional monomer and a saturatedcarboxylic acid; (B) at least one curing agent having functional groupsreactive with the functional groups of (A) selected from aminoplastresins, polyisocyanates, blocked polyisocyanates and mixtures thereof;and (C) at least one boron-containing compound selected from at leastone of boric acid, boric acid equivalents, and mixtures thereof.
 67. Thecoating composition of claim 66, wherein the curing agent (B) comprisesat least one aminoplast resin and at least one blocked polyisocyanatecomprising a tricarbamoyl triazine compound.
 68. The coating compositionof claim 57, wherein the first coating layer is formed from a curablecoating composition comprising: (A) at least one film-forming polymerhaving reactive functional groups; (B) at least one curing agent havingfunctional groups reactive with the functional groups of (A); and (C) atleast one boron-containing compound selected from boric acid, boric acidequivalents, and mixtures thereof.
 69. The coating composition of claim57, wherein the first coating layer is formed from a curable coatingcomposition comprising: (A) at least one film-forming acrylic polymercomprising functional groups selected from hydroxyl groups, carbamategroups and mixtures thereof; (B) at least one curing agent selected fromaminoplast resins, polyisocyanates, blocked polyisocyanates and mixturesthereof; and (C) at least one boron-containing compound selected fromboric acid, boric acid equivalents, and mixtures thereof.
 70. Thecoating composition of claim 68, wherein the boron-containing compound(C) is present in the curable coating composition in an amountsufficient to provide an amount of boron ranging from 0.001 to 5 percentby weight based on weight of total resin solids present in the curablecoating composition.
 71. In a curable coating composition used to form amulti-layer composite coating comprising two or more cured coatinglayers, said multi-layer composite coating comprising at least a firstcoating layer formed on a substrate and a second coating layer over atleast a portion of said first polymeric layer, wherein one or both ofsaid first coating layer and said second coating layer are formed fromsaid curable coating composition, and wherein in the absence of aboron-containing compound, said first coating layer and said secondcoating layer have poor interlayer adhesion, the improvement comprisingthe inclusion in said curable coating composition of a boron-containingcompound selected from at least one of boric acid, boric acidequivalents, and mixtures thereof in an amount sufficient to improve theinterlayer adhesion between said first coating layer and said secondcoating layer, wherein said first coating layer is formed from a curedcoating layer formed from a curable coating composition comprising: (A)at least one film-forming acrylic polymer comprising functional groupsselected from hydroxyl groups, carbamate groups and mixtures thereof;(B) at least one curing agent selected from aminoplast resins,polyisocyanates, blocked polyisocyanates and mixtures thereof comprisingan aminoplast resin and a blocked polyisocyanate comprising atricarbamoyl triazine compound; and (C) at least one boron-containingcompound selected from boric acid, boric acid equivalents, and mixturesthereof; and said second coating layer comprises a cured coating layerformed from a curable coating composition comprising: (D) at least onefilm-forming polymer having reactive functional groups selected fromhydroxyl groups, carbamate groups and mixtures thereof; (E) at least onecuring agent comprising functional groups reactive with the functionalgroups of (A); and (F) at least one boron-containing compound selectedfrom at least one of boric acid, boric acid equivalents, and mixturesthereof.
 72. In a curable coating composition used to form a multi-layercomposite coating comprising two or more cured coating layers, saidmulti-layer composite coating comprising at least a first coating layerformed on a substrate and a second coating layer over at least a portionof said first polymeric layer, wherein one or both of said first coatinglayer and said second coating layer are formed from said curable coatingcomposition, and wherein in the absence of a boron-containing compound,said first coating layer and said second coating layer have poorinterlayer adhesion, the improvement comprising the inclusion in saidcurable coating composition of a boron-containing compound selected fromat least one of boric acid, boric acid equivalents, and mixtures thereofin an amount sufficient to improve the interlayer adhesion between saidfirst coating layer and said second coating layer, wherein one or bothof said first coating layer and said second coating layer comprises acured coating layer formed from a curable coating compositioncomprising: (A) at least one film-forming acrylic polymer havingreactive functional groups comprising residues of a beta-hydroxygroup-containing monomer selected from at least one of: (i) the reactionproduct of an ethylenically unsaturated acid functional monomer and anepoxy functional compound having no ethylenic unsaturation; and (ii) thereaction product of an ethylenically unsaturated, epoxy functionalmonomer and a saturated carboxylic acid; (B) at least one curing agenthaving functional groups reactive with the functional groups of (A)comprising an aminoplast resin and a blocked polyisocyanate comprising atricarbamoyl triazine compound; and (C) at least one boron-containingcompound comprising a reaction product formed from the followingreactants: (i) at least one polysiloxane comprising having at least oneof the following structural units (I):R¹ _(n)R² _(m)SiO_((4-n-m)/2)  (I) wherein each R¹ independently isselected from H, a monovalent hydrocarbon group or a siloxane group;each R² is independently a group comprising OR′, where R′ is H or analkyl group having 1 to 20 carbon atoms; and m and n each represent apositive number fulfilling the requirements of 0<m<4; 0<n<4; and2≦(m+n)<4; and (ii) at least one boron-containing compound comprising atleast one of boric acid, boric acid equivalents, and mixtures thereof.73. The coating composition of claim 72, wherein the boron-containingcompound (C) is present in the curable coating composition in an amountsufficient to provide an amount of boron ranging from 0.001 to 5 weightpercent, based on weight of total resin solids present in the coatingcomposition.
 74. The coating composition of claim 68, wherein said firstcurable coating composition comprises a base coating composition andsaid second curable coating composition comprises a top coatingcomposition.
 75. The coating composition of claim 68, wherein said firstcurable coating composition comprises a substantially pigment-free basecoating composition, and said second curable coating compositioncomprises a substantially pigment-free top coating composition.
 76. Thecoating composition of claim 68, wherein said first curable coatingcomposition comprises a pigment-containing base coating composition, andsaid second curable coating composition comprises a pigment-containingtop coating composition.
 77. The coating composition of claim 68,wherein said first curable coating composition comprises apigment-containing base coating composition, and said second coatingcomposition comprises a substantially pigment-free coating composition.78. The coating composition of claim 68, wherein said first curablecoating composition comprises a substantially pigment-free base coatingcomposition, and said second curable coating composition comprises apigment-containing top coating composition.
 79. The coating compositionof claim 78, wherein said second curable coating composition comprisesan adhesive composition.
 80. The coating composition of claim 45,wherein said first polymeric layer is formed on a metallic substrate.81. The coating composition of claim 45, wherein said first polymericlayer is formed on an elastomeric substrate.
 82. The coating compositionof claim 45, wherein said first polymeric layer is formed on a substratecomprising a substrate and one or more polymeric layers.
 83. The coatingcomposition of claim 45, wherein said substrate comprises a substrateand one or more polymeric layers formed from one or more thermosettingfilm-forming compositions.
 84. A method for improving the intercoatadhesion of a multi-layer composite comprising two or more polymericlayers, at least one of which is formed from a thermosettingcomposition, said composite comprising at least a first polymeric layerformed on at least a portion of a substrate, and a second polymericlayer formed over at least a portion of said first polymeric layer,wherein in the absence of a boron-containing compound, said firstpolymeric layer and said second polymeric layer have poor interlayeradhesion, the improvement comprising the inclusion of at least oneboron-containing compound selected from boric acid, boric acidequivalents, and mixtures thereof in one or both of said first andsecond polymeric layers in an amount sufficient to improve theinterlayer adhesion of said first polymeric layer and said secondpolymeric layer, wherein the concentration of the boron-containingcompound at a surface region of a coating layer containing theboron-containing compound is greater than the concentration of theboron-containing compound in the bulk region of the coating layer. 85.The method of claim 84, wherein at least one boron-containing compoundis present in said first polymeric layer.
 86. The method of claim 84,wherein at least one boron-containing compound is present in said secondpolymeric layer.
 87. The method of claim 84, wherein at least oneboron-containing compound is present in said first polymeric layer andin said second polymeric layer.
 88. The method of claim 84, wherein saidboron-containing compound is selected from at least one of boric acid,borate ester, and mixtures thereof.
 89. The method of claim 88, whereinsaid boron-containing compound comprises boric acid.
 90. A method forimproving the intercoat adhesion of a multi-layer composite comprisingtwo or more polymeric layers, at least one of which is formed from athermosetting composition, said composite comprising at least a firstpolymeric layer formed on at least a portion of a substrate, and asecond polymeric layer formed over at least a portion of said firstpolymeric layer, wherein in the absence of a boron-containing compound,said first polymeric layer and said second polymeric layer have poorinterlayer adhesion, the improvement comprising the inclusion of atleast one boron-containing compound selected from at least one of boricacid, borate ester, and mixtures thereof in one or both of said firstand second polymeric layers in an amount sufficient to improve theinterlayer adhesion of said first polymeric layer and said secondpolymeric layer, wherein said boron-containing compound is selected fromat least one of acrylic borate ester, polysiloxane borate ester,polyester borate ester, polyurethane borate ester, and mixtures thereof.91. The method of claim 88, wherein said boron-containing compoundcomprises a borate ester selected from at least one oftriethanolamineborate, triisopropyl borate, trimethyl borate, triphenylborate trimethoxyboroxine triethanolamine borate; mannitol borate;n-propanol amine borate, trimethylolpropane borate, glycerol borate andmixtures thereof.
 92. The method of claim 84, wherein both the firstpolymeric layer and the second polymeric layer are formed fromthermosetting compositions.
 93. A method for improving the intercoatadhesion of a multi-layer composite comprising two or more polymericlayers, at least one of which is formed from a thermosettingcomposition, said composite comprising at least a first polymeric layerformed on at least a portion of a substrate, and a second polymericlayer formed over at least a portion of said first polymeric layer,wherein in the absence of a boron-containing compound, said firstpolymeric layer and said second polymeric layer have poor interlayeradhesion, the improvement comprising the inclusion of at least oneboron-containing compound in one or both of said first and secondpolymeric layers in an amount sufficient to improve the interlayeradhesion of said first polymeric layer and said second polymeric layer,wherein said boron-containing compound comprises the reaction productformed from the following reactants: (A) at least one polysiloxanecomprising at least one of the following structural units (I):R¹ _(n)R² _(m)SiO_((4-n-m)/2)  (I) wherein each R′ is independentlyselected from a monovalent hydrocarbon group or a siloxane group; eachR² independently is a group comprising OR′, where R′ is H or an alkylgroup having 1 to 20 carbon atoms; and m and n each represent a positivenumber fulfilling the requirements of 0<m<4; 0<n<4; and 2≦(m+n)<4; and(B) at least one boron-containing compound selected from at least one ofboric acid, boric acid equivalents, and mixtures thereof.
 94. The methodof claim 93, wherein at least one R² comprises OH.
 95. The method ofclaim 93, wherein said polysiloxane comprises one or more ungelled,organic polysiloxanes having reactive functional groups, saidpolysiloxane having the following structure (II) or (III):

where m has a value of at least 1; m′ ranges from 0 to 75; n ranges from0 to 75; n′ ranges from 0 to 75; each R, which may be identical ordifferent, is selected from H, OH, monovalent hydrocarbon groups,monovalent siloxane groups, and mixtures of any of the foregoing; andR^(a) comprises the following structure (IV):—R³—X  (IV) wherein —R³ is selected from an alkylene group, anoxyalkylene group, an alkylene aryl group, an alkenylene group, anoxyalkenylene group, and an alkenylene aryl group; and X represents agroup which comprises at least one reactive functional group selectedfrom selected from at least one of a hydroxyl group, a carboxyl group, aprimary amine group, a secondary amine group, an amide group, acarbamate group, a urea group, an anhydride group, a hydroxy alkylamidegroup, and an epoxy group.
 96. The method of claim 95, wherein thepolysiloxane is a reaction product formed from the following reactants:(A) a silicon hydride-containing polysiloxane having the followingstructure (V):

wherein the R groups are selected from H, OH, monovalent hydrocarbongroups, siloxane groups and mixtures thereof, wherein at least one ofthe groups represented by R is H, and n′ ranges from 0 to 100, such thatthe mole percent of hydrogen-bonded silicon atoms to non-hydrogen-bondedsilicon atoms ranges from 10 to 100 percent; and (B) one or morehydroxyl functional materials comprising at least one primary hydroxylgroup and at least one unsaturated bond capable of undergoinghydrosilylation reaction.
 97. The method of claim 96, wherein reactant(B) is a hydroxyl functional group-containing allyl ether selected fromat least one of trimethylolpropane monoallyl ether, pentaerythritolmonoallyl ether, trimethylolpropane diallyl ether and mixtures thereof;or an allyl alcohol.
 98. The method of claim 84, wherein the firstpolymeric layer is formed from a thermosetting composition comprising aboron-containing compound present in said thermosetting composition inan amount sufficient to provide an amount of boron ranging from 0.001 to5 percent by weight, based on weight of total resin solids present inthe thermosetting composition.
 99. The method of claim 84, wherein oneor both of said first polymeric layer and said second polymeric layercomprises a cured layer formed from a thermosetting compositioncomprising: (A) at least one film-forming polymer having reactivefunctional groups; and (B) at least one curing agent having functionalgroups reactive with the functional groups of (A); and (C) at least oneboron-containing compound selected from at least one of boric acid,boric acid equivalents, and mixtures thereof.
 100. The composite ofclaim 99, wherein the film-forming polymer (A) comprises a polymerselected from acrylic polymers, polyester polymers, polyurethanepolymer, polyether polymers, silicon-based polymers, and mixturesthereof.
 101. The method of claim 99, wherein the film-forming polymer(A) comprises an acrylic polymer, a polyester polymer and mixturesthereof.
 102. The method of claim 99, wherein the film-forming polymer(A) comprises an acrylic polymer.
 103. The method of claim 99, whereinthe film-forming polymer (A) comprises functional groups selected fromat least one of a hydroxyl group, a carboxyl group, an isocyanate group,a blocked polyisocyanate group, a primary amine group, a secondary aminegroup, an amide group, a carbamate group, a urea group, a urethanegroup, a vinyl group, an unsaturated ester group, a maleimide group, afumarate group, an anhydride group, a hydroxy alkylamide group, and anepoxy group.
 104. The method of claim 103, wherein the film-formingpolymer (A) comprises functional groups selected from hydroxyl groups,carbamate groups and mixtures thereof.
 105. The method of claim 102,wherein the film-forming polymer (A) comprises the residue of abeta-hydroxy group-containing monomer selected from at least one of (A)the reaction product of an ethylenically unsaturated acid functionalmonomer and an epoxy functional compound having no ethylenicunsaturation; and (B) the reaction product of an ethylenicallyunsaturated, epoxy functional monomer and a saturated carboxylic acid.106. The method of claim 99, wherein the curing agent (B) comprisesaminoplast resins, polyisocyanates, blocked isocyanates, polycarboxylicacids, polyanhydrides, polyepoxides, polyamines, polyols, and mixturesthereof.
 107. The method of claim 104, wherein the curing agent (B) isselected from aminoplast resins, polyisocyanates, blocked isocyanatesand mixtures thereof.
 108. The method of claim 105, wherein the curingagent (B) comprises at least one aminoplast resin and at least oneblocked isocyanate comprising a tricarbamoyl triazine compound.
 109. Themethod of claim 99, wherein both the first polymeric layer and thesecond polymeric layer are formed from a thermosetting composition. 110.The method of claim 109, wherein the first polymeric layer is formedfrom a thermosetting composition comprising: (A) at least onefilm-forming polymer having reactive functional groups; (B) at least onecuring agent having functional groups reactive with the functionalgroups of (A); and (C) at least one boron-containing compound selectedfrom boric acid, boric acid equivalents, and mixtures thereof.
 111. Themethod of claim 110, wherein the first polymeric layer is formed from athermosetting composition comprising: (A) at least one film-formingacrylic polymer comprising functional groups selected from hydroxylgroups, carbamate groups and mixtures thereof; (B) at least one curingagent selected from aminoplast resins, polyisocyanates, blockedisocyanates and mixtures thereof; and (C) at least one boron-containingcompound selected from boric acid, boric acid equivalents, and mixturesthereof.
 112. The method of claim 110, wherein the boron-containingcompound (C) is present in the thermosetting composition in an amountsufficient to provide an amount of boron ranging from 0.001 to 5 percentby weight based on total resin solids present in the thermosettingcomposition.
 113. A method for improving the intercoat adhesion of amulti-layer composite comprising two or more polymeric layers, at leastone of which is formed from a thermosetting composition, said compositecomprising at least a first polymeric layer formed on at least a portionof a substrate, and a second polymeric layer formed over at least aportion of said first polymeric layer, wherein in the absence of aboron-containing compound, said first polymeric layer and said secondpolymeric layer have poor interlayer adhesion, the improvementcomprising the inclusion of at least one boron-containing compoundselected from boric acid, boric acid equivalents and mixtures thereof inone or both of said first and second polymeric layers in an amountsufficient to improve the interlayer adhesion of said first polymericlayer and said second polymeric layer, wherein said first polymericlayer is formed from a thermosetting composition comprising: (A) atleast one film-forming acrylic polymer having reactive functional groupsselected from hydroxyl groups, carbamate groups and mixtures thereof;(B) at least one curing agent having functional groups reactive with thefunctional groups of (A), comprising an aminoplast resin and a blockedisocyanate comprising a tricarbamoyl triazine compound; and (C) at leastone boron-containing compound selected from boric acid, boric acidequivalents, and mixtures thereof; and said second polymeric layercomprises a cured layer formed from a thermosetting compositioncomprising: (D) at least one film-forming polymer having reactivefunctional groups; (E) at least one curing agent having functionalgroups reactive with the functional groups of (A); and (F) at least oneboron-containing compound selected from at least one of boric acid,boric acid equivalents, and mixtures thereof.
 114. A method forimproving the intercoat adhesion of a multi-layer composite comprisingtwo or more polymeric layers, at least one of which is formed from athermosetting composition, said composite comprising at least a firstpolymeric layer formed on at least a portion of a substrate, and asecond polymeric layer formed over at least a portion of said firstpolymeric layer, wherein in the absence of a boron-containing compound,said first polymeric layer and said second polymeric layer have poorinterlayer adhesion, the improvement comprising the inclusion of atleast one boron-containing compound selected from boric acid, boric acidequivalents and mixtures thereof in one or both of said first and secondpolymeric layers in an amount sufficient to improve the interlayeradhesion of said first polymeric layer and said second polymeric layer,wherein said first polymeric layer is formed from a thermosettingcomposition comprising: (A) at least one film-forming acrylic polymerhaving reactive functional groups selected from hydroxyl groups,carbamate groups and mixtures thereof; (B) at least one curing agentselected from aminoplast resins, polyisocyanates, blocked isocyanatesand mixtures thereof; and (C) at least one boron-containing compoundcomprising the reaction product formed from the following reactants: (i)at least one polysiloxane comprising at least one of the followingstructural units (I):R¹ _(n)R² _(m)SiO_((4-n-m)/2)  (I) wherein each R′ is independentlyselected from a monovalent hydrocarbon group or a siloxane group; eachR² independently is a group comprising OR′, where R′ is H or an alkylgroup having 1 to 20 carbon atoms; and m and n each represent a positivenumber fulfilling the requirements of 0<m<4; 0<n<4; and 2≦(m+n)<4; and(ii) a boron-containing compound comprising at least one of boric acid,boric acid equivalents, and mixtures thereof; and said second polymericlayer comprises a cured layer formed from a thermosetting compositioncomprising: (D) at least one film-forming polymer having reactivefunctional groups; (E) at least one curing agent having functionalgroups reactive with the functional groups of (A); and (F) at least oneboron-containing compound selected from at least one of boric acid,boric acid equivalents, and mixtures thereof.
 115. The method of claim114, wherein the boron-containing compound (C) comprises boric acidand/or boric acid ester.
 116. The method of claim 114, wherein theboron-containing compound (C) is present in the thermosettingcomposition in an amount sufficient to provide an amount of boronranging from 0.001 to 5 weight percent based on weight of total resinsolids present in the thermosetting composition.
 117. The method ofclaim 92, wherein said first thermosetting composition comprises a basecoating composition and second thermosetting composition comprises a topcoating composition.
 118. The composite of claim 92, wherein said firstthermosetting composition comprises a substantially pigment-free basecoating composition, and said second thermosetting composition comprisesa substantially pigment-free top coating composition.
 119. The method ofclaim 92, wherein said first thermosetting composition comprises apigment-containing base coating composition, and said secondthermosetting composition comprises a pigment-containing top coatingcomposition.
 120. The method of claim 92, wherein said firstthermosetting composition comprises a pigment-containing base coatingcomposition, and said second thermosetting composition comprises asubstantially pigment-free coating composition.
 121. The method of claim92, wherein said first thermosetting composition comprises asubstantially pigment-free base coating composition, and said secondthermosetting composition comprises a pigment-containing top coatingcomposition.
 122. The method of claim 121, wherein said secondthermosetting composition comprises an adhesive composition. 123.(cancelled)
 124. (cancelled)
 125. (cancelled)
 126. A substratecomprising a substrate and a coating composition according to claim 45over at least a portion of the substrate
 127. In a multi-layer compositeof two or more polymeric layers at least one of which is formed from athermosetting composition in solid particulate form, said compositecomprising at least a first polymeric layer formed on a substrate and asecond polymeric layer over at least a portion of said first polymericlayer, wherein in the absence of a boron-containing compound, said firstpolymeric layer and said second polymeric layer have poor interlayeradhesion, the improvement comprising the inclusion of at least oneboron-containing compound selected from boric acid, boric acidequivalents, and mixtures thereof in the polymeric layers formed fromthe thermosetting composition in solid particulate form, in an amountsufficient to improve the interlayer adhesion of said first polymericlayer and said second polymeric layer.
 128. The composite of claim 127,wherein said boron-containing compound is selected from at least one ofboric acid, boric acid ester, metal borate, derivatives thereof andmixtures thereof.
 129. The composite of claim 128, wherein saidboron-containing compound comprises a boric acid ester selected from atleast one of triisopropyl borate, trimethyl borate, triphenyl borate,trimethoxyboroxine, polysiloxane borate, acrylic borate, and mixturesthereof.
 130. The composite of claim 128, wherein said boron-containingcompound comprises a boric acid ester derivative selected from at leastone of triethanolamineborate, mannitol borate, n-propranol amine borate,trimetholpropane borate, glycerol borate, and mixtures thereof.
 131. Thecomposite of claim 127, wherein said boron-containing compound comprisesthe reaction product formed from the following reactants: (A) at leastone polysiloxane comprising at least one of the following structuralunits (I):R¹ _(n)R² _(m)SiO_((4-n-m/2)  (I) wherein each R¹, which may beidentical or different, represents H, OH, a monovalent hydrocarbon groupor a monovalent siloxane group; each R², which may be identical ordifferent, represents a group comprising one or more active hydrogens;and m and n each represent a positive number fulfilling the requirementsof 0<m<4; 0<n<4; and 2≦(m+n)<4; and (B) a boron-containing compoundselected from at least one of boric acid, boric acid equivalents, andmixtures thereof.
 132. The composite of claim 131, wherein at least oneR² comprises OR′, where R′ is H or an alkyl group having 1 to 20 carbonatoms.
 133. The composite of claim 131, wherein said polysiloxanecomprises one or more ungelled non-hydrolyzable organic polysiloxaneshaving reactive functional groups, said polysiloxane having thefollowing structure (II) or (III):

wherein: m has a value of at least 1; m′ ranges from 0 to 75; n rangesfrom 0 to 75; n′ ranges from 0 to 75; each R, which may be identical ordifferent, is selected from H, OH, monovalent hydrocarbon groups,monovalent siloxane groups, and mixtures of any of the foregoing; andR^(a) comprises the following structure (IV):—R³—X  (IV) wherein —R³— is selected from an alkylene group, anoxyalkylene group, an alkylene aryl group, an alkenylene group, anoxyalkenylene group, and an alkenylene aryl group; and X represents agroup which comprises at least one reactive functional group selectedfrom at least one of a hydroxyl group, a carboxyl group, a primary aminegroup, a secondary amine group, an amide group, a carbamate group, aurea group, an anhydride group, a hydroxy alkylamide group, and an epoxygroup.
 134. The composite of claim 127, wherein the first polymericlayer is formed from a thermosetting composition in solid particulateform comprising a boron-containing compound present in saidthermosetting composition in an amount sufficient to provide an amountof boron ranging from 0.001 to 5 percent by weight, based on weight oftotal resin solids present in the thermosetting composition.
 135. Thecomposite of claim 127, wherein one or both of said first polymericlayer and said second polymeric layer comprises a cured layer formedfrom a thermosetting composition in solid particulate form comprising:(A) at least one film-forming polymer having reactive functional groups;(B) at least one curing agent having functional groups reactive with thefunctional groups of (A); and (C) at least one boron-containing compoundselected from at least one of boric acid, boric acid equivalents, andmixtures thereof.
 136. The composite of claim 135, wherein thefilm-forming polymer (A) comprises at least one polymer selected from anacrylic polymer, a polyester polymer, a polyurethane polymer, apolyether polymer, a silicon-based polymer, and mixtures thereof. 137.The composite of claim 135, wherein the film-forming polymer (A)comprises an acrylic polymer, a polyester polymer, and mixtures thereof.138. The composite of claim 135, wherein the film-forming polymer (A)comprises functional groups selected from a hydroxyl group, a carboxylgroup, an isocyanate group, a blocked polyisocyanate group, a primaryamine group, a secondary amine group, an amide group, a carbamate group,a urea group, a urethane group, a vinyl group, an unsaturated estergroup, a maleimide group, a fumarate group, an anhydride group, ahydroxy alkylamide group, and an epoxy group.
 139. The composite ofclaim 135, wherein the curing agent (B) comprises aminoplast resins,polyisocyanates, blocked polyisocyanates, polycarboxylic acids,polyanhydrides, polyepoxides, polyamines, polyols, and mixtures thereof.